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Natural sesquiterpenoids
Braulio M. FragaInstituto de Productos Naturales y Agrobiología, CSIC, 38206-La Laguna, Tenerife,Canary Islands, Spain
Covering: 1996Previous review: 1997, 14, 145
1 Farnesane2 Monocyclofarnesane3 Bicyclofarnesane4 Nanaimoane, acanthodorane and isoacanthodorane5 Bisabolane6 á-Santalane and â-santalane7 Trichothecane, cuparane, herbertane, laurane and
gymnomitrane8 Chamigrane9 Carotane, acorane, cedrane, duprezianane, italicane
and anisatin group10 Cadinane, cubebane, copaane, oploponane, copaborn-
ane and picrotoxane11 Himachalane, longipinane and longibornane12 Caryophyllane, botrydiane and quadrane13 Humulane, alliacane, pentalenane, hirsutane, lacta-
rane, marasmane, precapnellane, capnellane, illudaneand africanane
14 Germacrane15 Elemane16 Eudesmane, valerane, oppositane and manicolane17 Vetispirane and nudenane18 Eremophilane, chiloscyphane and bakkane19 Guaiane, xanthane, pseudoguaiane, rotundane and
patchoulane20 Aromadendrane and bicyclogermacrane21 Pinguisane22 Miscellaneous sesquiterpenoids23 References
1 FarnesaneThe structure of the hydrocarbon caparratriene has beendetermined as 1. This compound has been isolated fromOcotea caparrapi and possesses significant growth inhibitoryactivity against leukemia cells.1 The sesquiterpenes 5-hydroxy-12-oxo-farnesol 2 and 5-acetoxy-12-hydroxyfarnesol 3 havebeen found in an extract of the aerial parts of Inula salso-loides.2 A novel furanosesquiterpene 4 has been obtained fromthe soft coral Lobophytum catalai, which has been collected inthe Andaman and Nicobar Islands.3 The structures of ‘primi-tive’ membranes have been shown to be formed by single-chainpolyprenyl phosphates.4 Feeding experiments with labelledacetates have been used to show that the dorid nudibranches,such as Archidoris odhneri and Archidoris montereyensis, canbiosynthesize terpenoid acid glycerides de novo.5 The bio-transformation of the acyclic terpenoid (2E,6E)-farnesol bythe plant pathogenic fungus Glomerella cingulata has beenstudied.6 The absolute configuration of (3S)-nerolidol, theprecursor of the acyclic homoterpene 4,8-dimethylnona-1,3,7-triene, has been determined by GC–MS analysis of the homo-terpene produced after feeding to various plants a mixture ofequal amounts of labelled (3S)- and (3R)-nerolidol deriva-tives.7 Two new farnesyl protein transferase inhibitors havebeen isolated from a Streptomyces strain.8 The stereochemicalcourse of human protein-farnesyl transferase has been shownto be similar to that of FPP synthase.9,10 New farnesylphosphonate derivatives of phenylalanine have been prepared
and used as inhibitors of farnesyl protein transferase.11 Thefull paper on the chemistry and biology of cylindrols, novelinhibitors of Ras farnesyl protein transferase, has appeared.12
Syntheses of oxocrinol,13 á-farnesene hydroperoxides14 andfuroic acid15 have been reported, whilst chiral syntheses of(+)-ipomeamarone16 and of several hydroxylated farnesanesesquiterpenes17 have been described. The synthesis and bio-logical evaluation of several farnesyldiphosphate derivativeshave been carried out.18,19,20 The electron-transfer photo-reaction between (E,E)-farnesol and 1,4-dicyanobenzene hasbeen studied.21 (E)-Nerolidol has been employed as startingmaterial in the preparation of racemic ambrox,22 whilstfarnesyl acetate has been used in a chiral synthesis of the samecompound, in which a lipase catalysed resolution of racemicdrimane-8,11-diol is involved.23
2 MonocyclofarnesaneTwo novel cyclonerolidol derivatives 5 and 6 have beenisolated from the liverwort Porella subobtusa.24 The newsesquiterpenes 7–9 have been found in an extract of the aerialparts of Artemisia chamaemelifolia.25 The new norisoprenoids10–13 have been obtained from the leaves of Apolloniasbarbujana.26,27 Another compound of this latter type 14 hasbeen isolated from Viburnum dilatatum.28 The structure of10-normegastigmane glycoric acid has been determined as 15.This compound has been found in Glycosmis arborea.29,30
Several megastigmane glycosides have been isolated fromAlangium premnifolium,31 Bunias orientalis,32 Cydonia vul-garis,33 Pistia stratiotes34 and Vitis vinifera.35 The absoluteconfigurations of rehmaionosides A–C, three ionone glycosidesfrom Rehmannia glutinosa, have been determined by chemicaland physicochemical methods.36
O O O
O
O
O O
O O O
O
R1OH
OR2
O
O
O
H
Ang = ; Epang = ; Meacr =
Epmeacr = ; Mebu = ; Vali =
Sen = ; (CO)Pri = ; Tig =
1
4
2 R1 = O; R2 = H3 R1 = OH,H; R2 = Ac
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The structure of an antibacterial sesquiterpene, previouslyobtained from Premna oligotricha, has been revised to 16 onthe basis of its chemical synthesis.37 The total synthesis and theabsolute configuration of riccardiphenols A and B have beenreported.38 Syntheses of theaspirone and vitispirane have beendevised.39 Two independent syntheses of the potent antiulcero-genic compound (+)-cassiol40,41 and its enantiomer (")-cassiol42 have been accomplished this year. The first enantio-selective syntheses of (")-pallescensone and (")-ancistrodialhave been reported.43 A rapid synthesis of an intermediate 17for the preparation of monocyclofarnesyl derivatives has beendescribed.44
The natural occurrence of abscisic acid in Portugueseheather honey has been determined by HPLC analysis.45
A conformational analysis of ABA analogues, produced byCercospora cruenta, has been carried out.46 The role of thehydroxy group in the activity of abscisic acid has been evalu-ated using derivatives, with a methyl ether at C-1, in thebioassays.47 Optically active forms of oxygenated analogues ofABA have been tested to evaluate its biological activity.48
3 BicyclofarnesaneThe isolation of isodrimenediol 18, a possible intermediate inthe biosynthesis of drimane sesquiterpenes from Polyporus
arcularius, has been described.49 The two novel endothelin typeB receptor antagonists RES-1149-1 19, RES-1149-2 20,50
6-epi-albrassitrol 21 and 12-hydroxy-6-epi-albrassitrol 2251
have been obtained from Aspergillus species. Compound 20has also been isolated together with 23 from another species of
this genus, Aspergillus ustus.52 A revision of the absoluteconfiguration of the drimane sesquiterpene 24 has beenreported. This compound had been obtained from Aspergillusoryzae.53 The new sesquiterpene 2á-hydroxyisodrimeninol 25has been found in cultures of a fungus of Pestalotiopsis genus,which is associated with species of Taxus.54 The epicuticularwax of the fern Nephrolepis biserrata contains the threedrimane sesquiterpenes 26–28.55 A compound Sch-65676 29,which shows inhibitory activity against the cytomegalovirusprotease, has been obtained from the fermentation broth of afungal culture,56 whilst the substance BE-40644 30, a newinhibitor of the human thioredoxin system, has been found incultures of an Actinoplanes species.57 The genus Stachybotrysis also a good source of novel endothelin receptor antagonists,such as the lactam 31, stachybocin A 32 and other ana-logues.58,59,60 Another fungus Memnoniella echinata containsthe new IMPase inhibitors ATCC 20998A 33 and ATCC20998C.61 The levels of the sesquiterpenes polygodial and9-deoxymuzigadial in the foliage of several New Zealandpopulations of Pseudowintera colorata have been determinedusing HPLC and NMR methods.62 Known drimane, bisab-olane and pinguisane sesquiterpenes have been isolated from acell suspension culture of the liverwort Porella vernicosa.63
The brown alga Dictyopteris undulata contains a newsesquiterpene-substituted benzoquinone with antifeedantproperties, which has been named cyclozonarone 34.64
The novel sesquiterpenes deoxyspongiaquinone 35, (E)-chlorodeoxyspongiaquinone 36, spongiaquinol 37 and (E)-chlorodeoxyspongiaquinol 38 have been isolated from amarine sponge of the Euryspongia genus, collected at the GreatAustralian Bight.65 The five new drimane derivatives 39–43have been obtained from the sponge Dysidea fusca,66 whilst thetwo sesquiterpenes 44 and 45 have been found in Dysideafragilis, collected in the lagoon of Venice.67 The absolute
OMe
OH
OH
AcO
CO2H
OH OH
OH
O
O
HO
OH
HO
OH
AcO
HO HO OH
OH
OH
OH OH
HO
OH
OH
HO
78
14
5 6
7 ∆7(8)
8 ∆7(14)
9
10 11
12 13
14 15
OO
C6H5(CO)O
OH OH
16 17
O
O
HO
CHO
O
O
HO
HOOH
OHHO
OHOH CHO
O
O
O R1
R2
OH
18 19
20
24 25
21 R1 = β-OH,H; R2 = H22 R1 = β-OH,H; R2 = OH23 R1 = O; R2 = H
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stereochemistry of puupehenone and related metabolites hasbeen determined.68 A cytotoxic red dimer of this sesquiterpene,
dipuupehedione 46, has been isolated from a New Caledonianmarine sponge of the genus Hyrtios.69
A general strategy for the synthesis of drimane sesquiter-penes, exemplified by the preparation of siccanin, has beendeveloped.70 A racemic synthesis of cinnamolide and methyl-enolactocin has been described,71 whilst the enantioselectivesynthesis of (+)-avarol and (+)-avarone,72,73 and that of theirenantiomers,73 have been reported. A synthesis of variousmodel compounds for the central tricyclic ring system ofpopolophuanone E has been described.74
4 Nanaimoane, acanthodorane and isoacanthodoraneThe biosynthesis of nanaimoal, acanthodoral and isoacantho-doral in the dorid nudibranch Acanthodoris nanaimoensis hasbeen investigated.75 Studies of the synthesis of these sesquiter-penes have also been reported.76
5 BisabolaneNidulal 47 is a new bisabolane sesquiterpene with biologicalactivity, which has been found in an extract of the basidio-mycete Nidula candida.77 Four new sesquiterpene polyol esters48–51 have been isolated from Cremanthodium ellisi.78 Sevennew sesquiterpenes 52–58 have been obtained from the aerial
OO
O
OO
O
O
CHO
CHO
HO
OH
HO
HO
HN O
N N
OOH
O
OO
R1
AcO
HO
HO
HO
OH
OH
AcO
R2
CHO
CHOHO
HO CO2H
29
30 31
32
33
26 R1 = R2 = H27 R1 = OAc; R2 = H28 R1 = H; R2 = OAc
O
O
OMe
O
O
OH
HO
OMe
MeO
OMe
O
OMeO
OMe
OH
HOCl Cl
34 35
36 37 38
O
O O O
O
O
O
OAc
OAc
O
O O
O
O
OO
O
OH
HO
CO2H
CHO
HO
HO
OH
39 40 41
42 43 44
45 46
OHC
O O
O
O
OH
R3
R4O
HOH
OAngR2O
OH
OR1
O(CO)Pri
47 48 R1 = R3 = R4 = H; R2 = (CO)Pri
49 R1 = Ac; R2 = R3 = H; R4 = (CO)Pri
50 R1 = Ac; R2 = (CO)Pri; R3 = R4 = H51 R1 = R4 = H; R2 = (CO)Pri; R3 = OH
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parts of Achillea cretica.79 The bisabolane derivative 59 hasbeen found in an extract of the foliage of Fitzroya cupres-soides,80 whilst the bisabolane endoperoxides 60 and 61 havebeen isolated from the aerial parts of Eupatorium rufescens.These metabolites showed schizonticidal activity againstPlasmodium falciparum.81 The gum exudates of Commiphorakua contain the new sesquiterpene 62.82 The isolation andstructural determination of the bisabolane derivative 63 has
been reported. This compound has been obtained from theheartwood of Juniperus formosana.83 The known antifoulingsesquiterpene 3-isocyanotheotheonellin 64 has been found inextracts of four nudibranches of the family Phyllidiidae.84
The synthesis of turmeronol B has been accomplished.85
The ultraviolet irradiation of isoperezone acetate has beenstudied.86
6 á-Santalane and â-santalaneTwo new sesquiterpenes á-santaldiol 65 and â-santaldiol66 have been obtained from the heartwood of Santaluminsulare.87 A new enantiospecific synthesis of á-santalanederivatives has been described.88
7 Trichothecane, cuparane, herbertane, laurane andgymnomitraneTrichothecinols A, B and C 67–69 are potent antitumorpromoting sesquiterpenoids, which have been isolated fromthe fungus Trichothecium roseum.89 A study of tricoverroidstereoisomers, produced by another fungus Myrotheciumverrucaria, has been carried out.90 The biosynthesis of the
trichothecene 3-acetyldeoxynivalenol has been investigated.91
Enzymatic formation of multiple sesquiterpene skeletons, bygenetic alteration of the trichodiene synthase active site, hasbeen reported.92 15-Hydroxytrichodiene 70, produced byhydroxylation of trichodiene, has been obtained in trans-formed Nicotiana tabaccum cell suspension cultures, expressinga trichodiene synthase gene from Fusarium sporotrichioides.93
The results of these two last studies demonstrate that thealteration or introduction of a sesquiterpene gene can resultin the formation of new sesquiterpene metabolites. Thesesquiterpene hydrocarbons â-bazzanene, á-barbatene andâ-barbatene, which are characteristic constituents of liver-worts, have been identified for the first time as components ofa higher plant, Meum athamanticum.94
An enantioselective synthesis of (")-cuparene and (")-ä-cuparenol has been described.95 Two new herbertane sesquit-erpenes 71 and 72 have been found in an extract of theliverwort Herbertus aduncus, whilst the known sesquiterpenesherbertene and á-herbertenol have been obtained fromHerbertus borealis.96 Total syntheses of herbertenediol,97
herbertenolide, á-herbertenol, â-herbertenol,98 tochuinylacetate and dihydrotochuinyl acetate have been reported.99 Anenantiocontrolled100 and a racemic101 synthesis of filiforminhave been described. A new gymnomitrane 73 and a novelnorgymnomitrane derivative 74 have been isolated from theliverwort Jungermannia truncata, collected in Malaysia.102
CO2HCO2H
O
OH
O O
OH
O
O
OOH
O
OHOH
HHOH
HO
HAcO
HHO
HHO
HAcO
HOHO
R
52 53 54
55 56 57 R = α-OH58 R = β-OH
OH
H
OO
OO
H
H
H
H
H
H
OH
OH
O
OH
H
CN
59 60
61 62
63 64
OH
OH
OH
OH
65 66
O
R1O
O
O
OHR2
7067 R1 = O; R2 = OH68 R1 = α-OH,H; R2 = H69 R1 = α-OH,H; R2 = OH
OH
OH
R
OH
OH H
71 R = CHO72 R = CO2Me
73 74
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8 ChamigraneA new approach to the synthesis of racemic á-chamigrene hasbeen reported.103
9 Carotane, acorane, cedrane, duprezianane, italicane andanisatin groupThe structure and stereochemistry of fersorin 75 and fersoridin76 have been reported. These new carotane sesquiterpenes
were obtained from the roots of giant fennel, a Ferulaspecies.104 Another two compounds of this type, isoferuoneand 2,3-epoxyakichenol, have been isolated from Ferulajaeschkeana.105
The chromatography of a methanolic extract of Acoruscalamus gave six novel acorane derivatives 77–82, which were
shown to inhibit the germination of lettuce seeds.106 Anotheracorane sesquiterpene 15-hydroxyacora-4(14),8-diene 83 hasbeen obtained from the heartwood of Juniperus chinensis.107
This plant also contains a cedrane sesquiterpene, cedr-3-en-15-ol 84 and a duprezianane derivative, junipercedrol 85.The latter possesses a new skeleton.108 Another species ofthis genus, Juniperus thurifera, produces the sesquiterpenesá-duprezianene 86, â-duprezianene 87 and sesquithuriferol 88.This last compound was transformed by solvolytic rearrange-ment into 86 and 87, confirming the structure of theduprezianane skeleton by chemical methods.109
The biotransformation of cedrol and related compounds byMucor plumbeus has been investigated.110 Racemic syntheses ofá-biotol, â-biotol111 and Ä2-cedrene112 have been described.The oxidation of the hydrocarbon italicene has been studied.113
A novel sesquiterpene lactone, 3-benzoylpseudoanisatin 89,has been found in the pericarps of Illicium dunnianum.114
Another species of this genus, Illicium verum, contains theneurotropic sesquiterpenoids veranisatin A 90, veranisatin Band veranisatin C.115
10 Cadinane, cubebane, copaane, oplopanane, copabornaneand picrotoxaneThe structure of 10-isocyano-4-cadinene has been determinedas 91. This sesquiterpene has been found in extracts ofnudibranches of the family Phyllidiidae and showed anti-fouling activity against larvae of Balanus amphitrite.84 Threenew cadinane sesquiterpenes 92–94 have been identified as
components of species of the genus Baccharis.116 Other com-pounds of this type, á-hinokienol 95 and â-hinokienol 96, andthe cubebane derivative 97 have been isolated from the leaf oilof Chamaecyparis obtusa. In this study, the absolute configura-tions of 95 and 96 were established by synthesis from (")-menthone.117 The sesquiterpene (+)-10á-hydroxy-4-muurolen-3-one 98, a new inhibitor of leukotriene biosynthesis, has
75 R = H76 R = OAng
HO
R
O
O
OH
R
81 R = α-H82 R = β-OH
83
77 R = H78 R = Ac
O
OR
O
O
R
79 R = H80 R = OH
OH
H H
OH
HOH
H
89 15
84
86 ∆8(9)
87 ∆8(15)
85
88
O
O
OO
OMeC6H5(CO)O
O
O
O
HO OH
OH
HO
HO
89 90
H H
H
HO
HOH
H
H
OH
H
H
OH
NC
O
91 92
93 94
HO
H
R
O
H
OH
97 9895 R = α-OH96 R = β-OH
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been obtained from fermentations of a Favolaschia species.118
Other inhibitors of this type have been found in Leutinelluscochleatus.119 The cadinane derivatives 99 and 100–102 havebeen isolated from Artemisia chamaemelifolia25 and Fitzroya
cupressoides,80 respectively. The heartwood of Juniperus for-mosana contains (")-15-hydroxycalamenene 103.83 Thesesquiterpene o-naphthoquinones 104–107 have been isolated
from the root bark of Ulmus davidiana. Their antioxidativeactivities were determined by a thiobarbituric acid methodusing rat liver microsomes.120,121 Other antioxidative sesquit-erpenes, 7-hydroxy-3,4-dihydrocadalin and 7-hydroxycadalin,have been found in the dried flowers of Heterotheca inuloides.These compounds also showed cytotoxic activity.122 The novelfuranosesquiterpene 108 has been obtained from Bursera
leptophloeos.123 Several sesquiterpene glycosides, which havebeen named alangicadinosides A–E, have been isolated fromAlangium premnifolium.124 The absolute stereostructure of(1S,4S)-cis-5-hydroxycalamenene 109 has been revised to(1R,4R)-cis-5-hydroxycalamenene utilizing X-ray analysis.This compound has now been isolated from the liverwortBazzania trilobata.125 The complete 1H and 13C NMR spectraof ä-cadinene have been assigned. This sesquiterpene hydro-carbon has been obtained from a Juniperus species.126 Purifi-cation of (+)-ä-cadinene synthase from bacteria-inoculatedGossypium hirsutum has been reported,127 whilst the cloning and
heterologous expression of a second (+)-ä-cadinene synthasefrom Gossypium arboreum have been described.128 Synthesesof oxo-T-cadinol,129 halipanicine,130 hibiscoquin one131 Cand 7-demethyl-2-methoxy-calamenene132 have been accom-plished. An asymmetric synthesis of (+)-apogossypol hexa-methyl ether has been devised.133 An enantiomerically pureform of an intermediate in the synthesis of (+)-heptelidic acidhas been prepared.134
A review on the structure, biosynthesis and functions ofartemisinin (qinghaosu) has appeared.135 A new artemisinicacid analogue has been obtained from the mature stems ofTithonia diversifolia.136 The assignment of the 1H NMR signalsof artemisinic acid has been revised,137 whilst the 13C NMRspectra of á- and â-dihydroartemisinin have been assigned.138
The cytotoxicity of several artemisinin derivatives has beenevaluated.139 The production of methyl 3-oxoartemisinate bybiotransformation of methyl artemisinate with suspension cellcultures of Mentha piperita has been studied.140 The isolationof clones of Artemisia annua, containing high amounts ofartemisinin141 and artemisinic acid142 have been reported. Animmunoquantitative analysis of artemisinin using polyclonalantibodies has been developed.143 Ferrous ion induced thecleavage of the peroxy bond in artemisinin and its derivatives.DNA damage due to this process has been observed and maybe responsible for the antimalarial activity of these sub-stances.144 On the other hand, the rearrangements of artemisi-nin in the presence of heme and non-heme iron() and iron()have been investigated.145,146 The biotransformation of thesemisynthetic sesquiterpene artemether, using Cunninghamellaelegans and Streptomyces lavendulae, has been studied.147
Novel asymmetric total syntheses of (+)-artemisinin,148 (")-artemisinin D and (")-arteannuin D149 have been described.A radiolabelled synthesis of 14C-artemisinin has beenreported.150 The preparation of a new artemisinin dimer hasbeen achieved.151 Artemisinic acid has been converted into(")-fabianane in seven steps.152 An efficient total synthesis of(")-10-desmethylarteannuin B has been described.153
The novel sesquiterpenes 4-hydroxycopa-2-ene 110 and2á-hydroxycopa-3-ene 111 have been obtained from apetrol extract of Entandrophragma cylindricum.154 Two newbioactive oplopanane derivatives tussilagonone 112 and
neotussilagolactone 113 have been isolated from Tussilagofarfara.155 The stereoselective synthesis of copaborneol by anintramolecular double Michael reaction has been reported.156
Picrotoximaesin 114 is a new sesquiterpene, which has beenisolated from the berries of Maesobotrya floribunda.157
11 Himachalane, longipinane and longibornaneA homosesquiterpene 3-methyl-á-himachalane 115 has beencharacterized as the main sex pheromone of Lutzomya
H H
HO
O
OH
OHH
R
99
102 103
100 R = α-OH101 R = β-OH
O O
O
O R2
R1OH
O
O
107104 R1 = CH2OH; R2 = Me105 R1 = Me; R2 = CO2Me106 R1 = Me; R2 = CH(OMe)2
O
O
OH
109108
O
O
MeCH
O
MeCH
HO OH
H
OHH
OMebu
HOMebu
H
H
OO
HO
110 111 112
113 114
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longipalpis, a diptera from Brazil.158 The himachalane deriva-tive 116 has been isolated from the foliage of Fitzroya cupres-soides.80 The structure of the sesquiterpene 117, which had
been obtained from Cedrus atlantica, has been resolved byX-ray analysis.159 The leaves of Artemisia argyi (Chinesemoxa) contain the novel longipinane derivative moxartenone118.160 Other sesquiterpenes with this carbon frameworká-longipin-2-en-3-one 119 and 12-hydroxy-á-longipinene 120have been isolated from Achillea millefolium161 and Juniperuschinensis,107,108 respectively. The acid rearrangement of
longipinane into arteaganane has been studied,162 whilst thephotochemical rearrangement of a longipinane derivative intoa vulgarone derivative and a compound with a new tricyclicskeleton, has been investigated.163 The structure of iso-culmorin has been determined as 121 by X-ray analysis. Thiscompound has been obtained from the marine fungus Kalli-chroma tethys.164 A stereoselective synthesis of longiborneolhas been reported.156
12 Caryophyllane, botrydiane and quadraneThe sesquiterpenes pestalotiopsin A 122 and pestalotiopsin B123 have been isolated from a Pestalotiopsis species, a fungusassociated with the bark and leaves of Taxus brevifolia.165 A
new trypanocidal sesquiterpene, lychnophoic acid 124, hasbeen found in a species of the genus Lychnophora.166 Therearrangements of caryophyllene oxide in acid medium167
and in tetracyanoethylene168 have been studied. The gastriccytoprotection of the antiinflammatory sesquiterpene â-caryophyllene in rats has been investigated.169
(")-Clovane-2á,9â-diol 125 is one of the componentsobtained from the aerial parts of Baeckea frutescens.170 Fivenovel bioactive sesquiterpenes, botryenalol 126, botryendial127, methyl acetyl botryenaloate 128, 10-epi-dihydrobotrydial
129 and 10-dehydroxydihydrobotrydialone 130, have beenisolated from cultures of the fungus Botrytis cinerea.171
Another two sesquiterpenes, previously isolated from thisfungus, botrydial and dihydrobotrydial, appear to be respon-sible for the phytotoxic activity of this microorganism.172 Thepresilphiperfolane sesquiterpene 131, compound 132, formed
by oxidative cleavage, and four silphiperfolane acids 133–136have been isolated from Artemisia chamaemelifolia.25 A formalasymmetric total synthesis of (")-isocomene has beenachieved,173 whilst a racemic synthesis of presilphiperfolan-9-ol has been carried out.174 An extract of the gorgonianSubergorgia suberosa contains a novel cytotoxic sesquiterpenesuberosenone 137. This is the first quadrane derivative foundin a marine species.175 The molecular structure of terrecy-clodiol 138, a derivative of the antifungal metabolite terrecyclicacid, has been determined by X-ray analysis.176
13 Humulane, alliacane, pentalenane, hirsutane, lactarane,marasmane, precapnellane, capnellane, illudane and africananeA highly functionalized humulane derivative 139 has beenisolated from an endophytic fungus of Taxus brevifolia.177 The
O
H
H
O
O
HH
H HO
OAc
115 116
117 118
OH
HH
H
HHOH
OH
OH119 120 121
O CO2H
H
OH
OMe
AcO
OH
AcO
HO
OMeHO
H
122 123 124
O O
CHOR
OAcH
OHOH
OAcH
OAcH
OH
H
HO
OH O
125
129 130
126 R = CH2OH127 R = CHO128 R = CO2Me
HH H
OH
H
HO2CHO2C
O
O
R
R
131 132
133 R = α-OMe134 R = β-OMe
135 R = α-Me136 R = β-Me
Fraga: Natural sesquiterpenoids 79
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total synthesis of two alliacane derivatives of marine origin hasbeen carried out.178 A synthesis of racemic pentalenene hasbeen reported.179 Four hirsutane derivatives 140–143 with
antibiotic properties have been obtained from cultures of thefungus Lentinus crinitus.180 Racemic syntheses of ceratopica-nol have been described.181,182 The syntheses of the linear andangular triquinane skeletons have been reported.183,184
Subvellerolactone C 144 is a new lactarane sesquiterpene,which has been found in an extract from the fruit bodies ofLactarius subvellereous.185 The trans-fused lactarane sesquiter-pene 3-O-ethyl-8-epi-9-epi-furandiol has been synthesizedand its structure determined by X-ray analysis.186,187 A
reinvestigation of an ethanolic extract of Lactarius vellereusafforded four new lactones with the marasmane skeleton145–148.188 Two dialdehydes with this skeleton, merulidial andisovelleral, react stereoselectively with the natural triketidetriacetic acid lactone giving pentacyclic pyranone adducts. Oneof these adducts, that formed with merulidial, was identicalwith a compound previously isolated from cultures ofMeruliustremellosus.189
A concise total synthesis of dactylol and 3á-epi-dactylol hasbeen devised.190 Two asymmetric syntheses of natural (")-Ä9(12)-capnellene have been described.191,192 The structure oflentinellone has been determined as 149. This protoilludanederivative has been obtained from submerged cultures ofLentinellus cochleatus.193 Two new active metabolites againstbacteria and phytopathogenic fungi, illudin C2 150 and illudin
C3 151, have been found in a culture filtrate of Coprinusatramentarius.194 The design, synthesis and antitumor activityof bicyclic and isomeric analogues of illudin M have beenreported.195 Normal and reverse phase HPLC methods havebeen established for the isolation of illudin M and illudin S,from extracts of fungi of the genus Omphalotus.196 An illudin Sderivative, (hydroxymethyl)acylfulvene, has been shown tohave antitumor properties.197 Two independent syntheses ofthe fern sesquiterpene pterosin Z have been carried out.198,199
An extract of the Colombian liverwort Porella swartzianacontains five africanane derivatives, caespitenone 152 andswartzianin A–D 153–156, two secoafricanane sesquiterpenes,secoswartzianin A 157 and secoswartzianin B 158, and one
norsecoafricanane norsecoswartzianin 159.200 Another africa-nane derivative 160 has been isolated from Porella subobtusa.24
The known sesquiterpene Ä9(15)-africanane has been obtainedfrom the soft coral Sinularia hirta.201 Dermatolactone 161 is a
cytotoxic sesquiterpene with a novel carbon skeleton, whichhas been found in an extract of an Ascomycete belonging tothe family Dermateaceae.202
O
OH
HH
HO
137 138
OHO
O
OH R1
O
H
HR1
139 140 R1 = H; R2 = O141 R1 = OH; R2 = O142 R1 = H; R2 = α-OH,H143 R1 = OH; R2 = α-OH,H
O
OH
H
O
OH
H
O
OR1
R1
O
O
HO
OH
H
H
Et
O
OH
144 145
146 147 R1 = H; R2 = OH148 R1 = OH; R2 = H
R
O
OH
O
H
H
OH
OH149 150 R = α-CH2OH
151 R = β-CH2OH
O
O
O R O
O
MeO2C
O
O
O
HO
HO
HHOHO
152 155
156 157
158 159
153 R = H2154 R = O
O
O
O
OAc
O
O
H
H
160 161
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14 GermacraneThe structure of 9-methylgermacrane B has been determined tobe a novel homosesquiterpene, which has been obtained fromthe sex pheromone glands of Lutzomyia longipalpis.203 Theminimum energy conformations of two sex pheromones, peri-planone A and periplanone B, of the American cockroach,Periplaneta americana, and of eleven structural analogueshave been calculated using molecular mechanics methods.204
The hydrocarbon germacrene C is the main constituent of theliverwort Preissia quadrata, collected in Germany.205 Anotherliverwort Porella swartziana contains the germacrane diketone162.200 The relative and absolute configuration of (+)-allohedycaryol 163 have been determined by synthesis of its
enantiomer.206 This compound had been isolated from Ferulacommunis. Another species of this genus Ferula leucographacontains the new sesquiterpene leucoferin 164.207 Two novelsesquiterpenes, parvigemone 165 and neolitrane 166, have been
found in an extract of the stems of Neolitsea parvigemma.208
The hydrocarbon germacrene A has been proposed to be anintermediate in the biosynthetic conversion of FPP to (")-aristolochene. Thus, when (7R)-6,7-dihydrofarnesyl diphos-phate was incubated with aristolochene synthase dihydroger-macrene was obtained.209 The biotransformation of allylicallyactivated (E,E)-cyclodeca-1,6-dienols by Cichorium intybus hasbeen studied.210
Many new germacrane lactones have been isolated fromnatural sources during 1996. The structures 167–190 representthe new germacranolides, whilst the structures 191–202 havebeen assigned to the heliangolides, 203–205 to the melam-polides, and 206 to the cis,cis-germacranolides (Table 1).There are several points to note in relation to these lactones.
Known germacranolides have been obtained from Cyrto-cymura cincta.214 The metabolites, mainly sesquiterpenes andsesquiterpene lactones, isolated from species of the subtribeGochnatiinae (tribe Mutisieae, family Compositae) have beenreviewed.222 The antiplasmodial activity and the cytotoxiceffects of aqueous extracts and sesquiterpene lactones fromNeurolaena lobata have been evaluated.223 The antibacterialactivity of several sesquiterpene lactones has been reported.224
Spectral data of chemical modification products of costunolidehave been described.225 However, costunolide has been shownto have DNA-damaging properties.226 The structure of
1(10)Z,4Z-hanphyllin has been determined using X-ray analy-sis.227 The acid cyclisation of 5-oxo-germacren-6,12-olide hasbeen investigated.228
15 ElemaneAn investigation of the aerial parts of Onopordon myriacan-thum afforded the elemane derivative 207 and the elemanolide208.217 The lactone 209 has been found as a component of theaerial parts of Centaurea nicaensis.229 Another compound ofthis type 210 has been obtained from the roots of Neolitseahiiranensis,230 whilst the novel lactam clavulinin 211 has beenisolated from the soft coral Clavularia inflata.231
16 Eudesmane, valerane, oppositane and manicolaneFour new eudesmane sesquiterpenes 212–215 have beenobtained from the liverwort Lepidozia vitrea,232 whilst thefuran–eusdemane 216 has been isolated from another liver-wort, Lophocolea heterophylla.233 The bisesquiterpene biatrac-tylode 217 has been found in an extract of the Chinesemedicinal herb Atractylodes marocephala.234 A study of Acoruscalamus led to the isolation of the two sesquiterpenes 218 and219.106 The aerial parts of Artemisia eriopoda235 and Artemisiamongolica236 contain the novel eudesmane derivatives 220–223and 224, respectively. The structures 225 and 226 have beenassigned to two metabolites isolated from Eremophila specta-bilis.237 Four new eudesmane derivatives pterodontic acid 227,1â-hydroxypterodontic acid 228, 3â-hydroxypterodontic acid229 and 2á,3â-dihydroxypterodontic acid 230 have been foundin the medicinal plant Laggera pterodonta.238 Another study ofthis plant afforded other eudesmanes and eudesmanoic gluco-sides.239 Eudesm-4(14)-en-3á,11-diol 231 is a new sesquiterpe-noid, which has been found in the heartwood of Neocallitropsispancheri.240 The structure of machikusanol has been deter-mined as 232. This compound has been isolated from thexylem of Persea japonica.241 The new sesquiterpene 233, whichpossesses antibacterial activity has been obtained from Epaltesmexicana.242 An investigation of a hexane extract of the aerialparts of Pluchea quitoc yielded four novel eudesmane deriva-tives 234–237.243 Other novel products of this type 238 and 239have been obtained from Senecio flammeus,244 and Tanacetum
162 163
O
O
OH
164 165 166
O
O
OO
OAc
OHO
CO
OH
O
OHO
OAng
O
Table 1 Sources of germacrane lactones
Source Ref.
GermacranolidesAnvillae garcinii 168, 169 211Artemisia pallens 167 212Carpesium nepalense 187–190 213Eirmocephala megaphylla 170 214Elephantopus mollis 172 215Inula salsoloides 179–181 2Mikania mendocina 186 216Onopordon myriacanthum 171 217Stevia maimarensis 173–178 218Stevia vaga 182–185 219
HeliangolidesBajaranoa sp. 191–197 220Mikania mendocina 198–199 216Stevia vaga 200–202 219
MelampolidesInula salsoloides 203, 204 2Stevia vaga 205 219
cis,cis-GermacranolidesAcanthospermuim australe 206 221
Fraga: Natural sesquiterpenoids 81
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OO O O O
O O
O
O
O
OH
O
O
O O
O
OO
O
O
OHHO
O
OOH
O
HO
O O
OR1
O
O
OH
O
O
R
O
O
OO O
O
R2
OAc
OR3
R2O
OMeacr
OAc
OH
OO
O O
O
O
O
OAc
O
O
O
Cl
O
O
OO
O
R3
OO
O
O
O
R2
OTig OH
R1
R1R2
OH
HO OR
OTigOH
OHOR1
HO
HO
OH
O
O
O
O
OAc
O
OH
O
O
O
OAc
O
O
O
CHO
O
O
O
O O
(CO)PriO
OAc
O
O
HO
OROH
O
O
O
R1
O
HO
199 200
205 206201 R = H202 R = OAc
203 R = H204 R = Vali
167 168 Partenolid-9-one 169 170 3-Deacylglaucolide B 171
172 173 R1 = R2 = H; R3 = OTig174 R1 = H; R2 = OH; R3 = Tig175 R1 = H; R2 = OH; R3 = 4-OHTig176 R1 = OH; R2 = OAc; R3 = Tig177 R1 = Tig; R2 = OH; R3 = H
178
186
197 198
179 R = H180 R = OH181 R = OAc
182 R1 = OAc; R2 = OH183 R1 = OAc; R2 = H184 R1 = H; R2 = OH185 R1 = H; R2 = OAc
187 R1 = Sen; R2 = CH2
188 R1 = Ang; R2 = CH2
189 R1 = Tig; R2 = CH2
190 R1 = H; R2 = β-Me,H
191 R1 = H; R2 = 5-AcOTig; R3 =
192 R1 = H; R2 = 5-AcOTig; R3 = α-OH, β-CH2Cl
193 R1 = OH; R2 = Tig; R3 =
194 R1 = OH; R2 = Tig; R3 = α-OH, β-CH2Cl
195 R = Ang196 R = Tig
OAc
HH
H
H
CO2Me
OO
OH
O
OHOH
O
CO2MeO
O
O
O
N
OOH
OOH
OHOH
OO OH
O
HOH
207 208
209 210
211
34
216
217
212 ∆4(15); R = H213 ∆4(15); R = β-OH214 ∆3(4); R = H215 ∆3(4); R = α-OAc
218 R = H219 R = OH
15
O
O
O
O
O
O
OH
OH
OH
R
R
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praeteritum,245 respectively. A new dinorsesquiterpene guay-ulone 240 with fungistatic properties has been isolated fromthe resin of Parthenium argentatum.246 This species also con-
tains five novel sesquiterpenes 241–245.247 The phytotoxicmetabolite zingibertriol 246 has been found in the fungusPyricularia oryzae.248 The structure of 5-O-acetyl-cuauhtemonyl-6-O-2*,3*-epoxy-2*-methylbutyrate, isolatedfrom Pluchea carolinensis, has been determined by X-rayanalysis.249 This technique has been also used in the structuraldetermination of emmotin-2 247.250
An efficient and stereoselective synthesis of (+)-á-cyperonehas been devised.251 (&)-Dihydrocarvone has been used asstarting material in the synthesis of (+)-12-hydroxy-á-cyperone, (+)-12-oxo-á-cyperone and (+)-3-oxo-eudesma-4,11(13)-dien-12-oic acid,252 whilst santonin has beenemployed in the preparation of (+)-â-cyperone, eudesma-3,5-diene,253 furanoeudesma-1,3-diene and tubipofurane.254 Amodified synthesis of racemic occidentalol has beenreported.255 A practical synthesis of enantiomerically pure(")-geosmin has been achieved.256
Several dihydroagafuran sesquiterpenes have been obtainedfrom members of the Celastraceae family: Celastrus flagel-laris,257 Celastrus hindsii,258 Celastrus orbiculatus259 andMaytenus buchananii.260
New eudesmanolides have been obtained from differentspecies (Table 2), and their structures shown to be 248–261.The cytotoxic and antibacterial activities of the sesquiterpenelactones isolated from Tanacetum praeteritum have been evalu-ated.267 The 1H and 13C NMR assignment of the alantolactonemoiety of the adduct of this lactone with (Z)--Cys-Ala-OMehas been reported.268 A short synthesis of the sesquiterpenelactone 1-oxoeudesma-2,4-dien-11â,12,6á-olide has beenachieved.269 A new (salen)-manganese() complex bearing asesquiterpene salicylaldehyde derivative has been used in the
CO2H CO2HHO
R
R
227 R = H228 R = OH
229 R = H230 R = OH
CO2Me
OH
OH
OH OH
O
OH
R
O
OHOH
HO
OH
OH
HO
220 221
224
225 226
222 R = O223 R = β-OH,H
OH
O
OOHEpangO
HO
HO
231 ∆4(15)
232 ∆4(5)233
45
15
CO2Me
O
OH
O O
OH
O
HO
OH
OH
AcO
AngO
AngO AngO
AcO
OH
HO OH
R236
237 238
239
234 R = α-OH235 R = β-OAc
O
OMe
O
O
R1
MeO R2
OH
OHHO CHOOH
OH
HO
240
247
241 R1 = Me; R2 = H2
242 R1 = H; R2 = H2
243 R1 = CH2OH; R2 = H2
244 R1 = Me; R2 = O245 R1 = H; R2 = O
246
Table 2 Sources of eudesmanolides
Source Eudesmanolides Ref.
Artemisia giraldii 248 261Artemisia herba-alba 249 262Artemisia lerchiana 250, 251 263Artemisia pontica 252–254 264Inula salsoloides 255 2Onopordon myriacanthum 257 217Stevia maimarensis 256 218Sarcandra glabra 261 265Tanacetum praeteritum 258 245Wedelia prostrata 259, 260 266
Fraga: Natural sesquiterpenoids 83
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catalysed epoxidation of unfunctionalized olefins with iodosyl-benzene and molecular oxygen–pivalaldehyde as terminaloxidant.270
A HPLC method for the analysis of valerenic acids inextracts of Valeriana officinalis has been described.271 Enantio-specific syntheses of (+)-valerane and (")-valeranone havebeen achieved,272,273 while a racemic synthesis of isovalerenolhas been reported.274 The sesquiterpene 262 has been isolated
from the marine sponge Acanthella cavernosa. This compoundinhibits the metamorphosis of Balanus amphitrite.275 Aracemic synthesis of axamide and axisonitrile has beendescribed,276 whilst enantioselective synthesis of (")-homalomelol A and homalomenol B has been reported.277 Anenantiospecific construction of the carbon skeleton associatedwith the antineoplastic sesquiterpene manicol 263 has beenaccomplished.278 Spectral data of several eudemanolidesobtained by epoxidation and cyclization of costunolide havebeen described.225
17 Vetispirane and nudenaneThe new sesquiterpene ethers 264 and 265 have been found inthe apolar part of Haitian vetiver oil.279 The effects of agaro-spirol and jinkoheremol, obtained from agarwood, on thecentral nervous system in mice have been investigated.280 Aracemic synthesis of the spirovetivane phytoalexin (&)-lubiminol has been achieved,281 whilst an enantiospecificsynthesis of (")-solavetivone has been carried out.282 TheTaiwanese liverwort Mylia nuda contains the sesquiterpenenudenoic acid 266, which possesses a new carbon skeletonnamed nudenane, probably derived from vetisperane.283
18 Eremophilane, chiloscyphane and bakkaneAn eremophilane derivative 267 has been found in an extractof Pedicularis striata,284 whilst the new sesquiterpene ethers268 and 269 have been isolated from vetiver oil.279 Thestructure of ligulaverin A 270 has been determined by X-ray
analysis. This compound, which has been isolated fromLigularia veitchiana, possesses a new carbon framework poss-ibly derived from an intramolecular Diels–Alder reaction of a
hydroxymethylacrylate ester of an eremophilane sesquiter-pene.285 Another species of this genus, Ligularia virgaurea,contains the novel sesquiterpenes virgaurin A 271, furano-mexican-9-en-8-one and 9â,10â-epoxyfuranomexicanan-8-one.286 The phytotoxicity and the electrochemical properties ofthe herbicide cacalol and its derivatives, isolated from the rootsof Psacalium decompositum, have been investigated.287,288
Four new dinoreremophilane derivatives with a rare skel-eton eremopetasinorone A 272, eremopetasinorone B 273,eremopetasinol 274 and epoxyeremopetasinorol 275, and fournovel eremophilenolides eremosulfoxinolide A 276, eremo-sulfoxinolide B 277, 3â,8á-dihydroxy-6â-methoxyeremophil-7(11)-en-12,8-olide 278 and 2â-hydroxyeremophil-7(11)-en-12,8â-olide 279 have been obtained from the rhizomes of
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
R
R2
O
O
OH
O
OO
OO(CO)Pri
OHOH
OR1
OH
OH
OHOH
AcO
OH
OH
O
OR
OH
OH
OHOR
HO H
H
CHO
R
248 249 252 R = various
257 258 261
250 R = CH2
251 R = α-OH,Me253 R = β-OH254 R = α-OVali
255 R1 = H; R2 = α-Me,H256 R1 = various; R2 = CH2
259 R = Ang260 R = Tig
OO
SCN
HO
OOH
262 263
O
R
CO2H
264 R = CH2265 R = OMe,H
266
O
O
OH
O
O
O
O O
OH
O
OH
OH
H
OOH
267 268 269
270 271
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Petasites japonicus.289 Another four lactones 280–283 and twonew secoeremophilane derivatives, 284 and 285, were alsoisolated from this species.290,291 The roots of Roldana sessili-folia292 contain three new eremophilanolides 286–288. Anothertwo compounds of this type have been obtained from Ligulariaintermedia.293 The eremophilane derivative 289 has been foundin Senecio hualtaranensis, whilst a closely related species,Senecio fabrisii, does not contain eremophilane derivatives.294
The chiloscyphane derivative 290 has been isolated from theliverwort Jungermannia vulcanicola.295 A highly stereoselectivesynthesis of an A-ring functionalized bakkane has beenachieved.296 The synthesis of spirolactones related to thebakkenolides has been accomplished.297
19 Guaiane, xanthane, pseudoguaiane, rotundane andpatchoulaneGuaiswartzianin A 291 and guaiswartzianin B 292 are twoguaiane sesquiterpenes, which have been isolated from Porellaswartziana.200 The essential oil from the heartwood of Thuja
occidentalis298 contains the two guaiane derivatives 293 and294. A 1,5,11-trihydroxyguaiane has been isolated from Caryo-daphnosis tonkinensis,299 whilst the compounds 295–297 havebeen obtained from Viburnum awabuki.300 Other guaianederivatives valeracetate 298 and pancherione 299 have been
obtained from Valeriana officinalis301 and Neocallitropsispancheri,240 respectively. The bis-sesquiterpene assafulvenal300, which is formed from a guaiane and a patchoulanesesquiterpene, has been isolated from the root bark of Joan-nesia princeps, and its structure has been determined by X-rayanalysis.302 A guaiazulene pigment 301 has been found in thegorgonian Calicogorgia granulosa.303 Known guaiane deriva-tives have been obtained from Lepechinia urbaniana304 andRubus rosifolius.305 Another known sesquiterpene with cyto-toxic properties, guaianediol 302, has been isolated from theRed Sea soft coral Sinularia gardineri.306 Koike et al.307 havereported the synthesis of natural dictamnol, but later De Grootet al.308 have prepared cis-dictamnol stating that dictamnolhas a trans- and not a cis-fused hydroazulene system. Thus,the structure of dictamnol (Nat. Prod. Rep., 1995, 12, 313,structure 273) has been revised to 303. The synthesis of (")-clavukerin A and (")-11-hydroxyguaiene has been achieved,but the spectroscopic data of the latter did not match with
OO
O O
O
OAngRO
H
H
HO
H
R
S
O
O
S
O
O
OO
HO
OMe
H
OO
HHO
H
OH
:
:
5
6
272 R = α-Me273 R = β-Me
274275 5,6-epoxy
276 R =
277 R =
278
279
OO
OAng
H
OO
OR2
H R1
OO
OH
H OHO
OH
OAng
O OOH
OAng
OOH
O
O O
O
HO
HO
OH
OMe
Cl
O
HO
280
283 284
285
281 R1 = OH; R2 =
282 R1 = R2 = H
OO
OHO
O
OH R
O
O(CO)Et
HO
O
OH OAng
OH OH
288
289 290
286 R = H287 R = OH
O
O
OH
H
H
H
HO
291 R = ∆4(15)
292 R = ∆3(4)
293 294
OH OH
OH
OOAc
O
OH
HHOO
HOO
H
H
H
H
HH
295 296
297 298 299
Fraga: Natural sesquiterpenoids 85
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those reported for the natural compound.309 An asymmetricsynthesis of the perhydroazulene (")-isoclavukerin A hasbeen achieved.310
The sources of the new guaianolides 304–320 that have beenisolated from plant species during the period of coverage ofthis review are listed in Table 3. A reinvestigation of theCaribbean sea plume, Pseudopterogorgia americana, affordedthe novel lactones americanolide A 321, americanolide B 323and americanolide C 322.316 The structures of the guaianolides,canin, tanaparthin á-peroxide, secotanapartholide A, arte-canin, tanaparthin â-peroxide and secopartholide B, present inthe feverfew, Tanacetum parthenium, have been revised byX-ray analysis and chemical correlations. The activity ofsome of these compounds as inhibitors of human bloodplatelet function has been determined, and its relation tomigraine prophylaxis by feverfew has been discussed.317
Known guaianolides have been obtained from Artemisiapedemontana.318 The production and characterization of poly-clonal antibodies against the bitter sesquiterpene lactones of
chicory, Cichorium intybus, has been described.319 The crystalstructure of 11â,13-dihydromicheliolide has been reported.320
The absolute configuration of chlorojanerin has been deter-mined by X-ray analysis.321 The circular dichroism spectra ofeight guaianolides, obtained from Centaurea scoparia, havebeen studied.322
The new xanthanolide glycosides 324, 325 and 326, 327 havebeen isolated from the flowers of Arnica amplexicaulis323 andthe aerial parts of Xanthium spinosum,324 respectively. Thestructure of the pseudoguaianolide hymenograndin B has beendetermined as 328. This lactone has been found in Hymenoxysbrachyactis.325 A biosystematic study of Argentinian species ofGaillardia has been carried out, using the pseudoguaianolidesas chemotaxonomical markers.326 A species of this genus,Gaillardia grandiflora,327 contains the new lactones 329 and330. The cytotoxicity and the NMR spectral assignments ofergolide and bigelovin have been described.328 The phyto-toxicity of parthenin on aquatic weeds has been studied.329
A formal enantiospecific synthesis of (+)-carpesiolin, (+)-confertin, (")-damsin, (")-helenalin, (+)-bigelovin, (+)-mexicanin I and (+)-linifolin A has been reported.330
The lactones rotundopontilides A–F 331 possess the uncom-mon rotundane skeleton. They have been obtained from the
OHC
H OH
HO H
H
HO H
300
301
302
303
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
OH
O
O
OR2
ROAc
R
OAng
H H
H OH
HOH
H
OMeacr
H
H
H
H
OH
OH
GlcO H
HHO
HO H
H
OH OH
H
H
O
O
O
O
O
H
HO
H
R1
R
HO HO
HO
R OH
304 Moxartenolide 305 R = α-Me306 R = β-Me
307 Gnaphaloide 308 R1 = α-CH2OH; R2 = H309 R1 = α-CH2OH; R2 = Ac310 R1 = β-CH2OH; R2 = H311 R1 = β-CH2OH; R2 = Ac
312
313 314 315 318
323321 R = OH322 R = H
316 R = CH2
317 R = α-Me,H
319 R = CH2
320 R = α-OH,Me,
Table 3 Sources of guaianolides
Source Guaianolides Ref.
Arnica mollis 313 311Artemisia argyi 304 161Artemisia lerchiana 314, 315 263Crepis rhoeadifolia 305, 306 312Mikania mendocina 316–318 216Picris radicata 319, 320 313Ptilostemmon gnaphaloides 307 314Stevia vaga 308–311 219Tanacetum argenteum 312 315
86 Natural Product Reports, 1998
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aerial parts of Artemisia pontica.331 The stereoselective syn-thesis of (&)-isonorpatchoulenol has been achieved.332 Theasymmetric synthesis of vulgarolide and deoxocrispolide hasbeen accomplished.333
20 Aromadendrane and bicyclogermacraneThe sesquiterpene 332 has been isolated from the marinesponge Acanthella cavernosa. This compound inhibits themetamorphosis of the barnacle Balanus amphitrite.275 The newaromadendrane derivative isoplagiochilide 333 and the 2,3-secoaromandendrane 334 have been found as a constituent of
the liverworts Plagiochila elegans334 and Heteroscyphus coali-tus,335 respectively. Three ent-alloaromadendranes 335–337,two ent-2,3-secoaromadendrane 338 and 339, and one bicyclo-germacrane 340 have been obtained from cultured cells ofHeteroscyphus planus.336 The first natural occurrence of the(")-ledol has been reported. This metabolite has beenobtained from another liverwort, Cephaloziella recurvifolia.337
In a study of the constituents of Dicranolejeunea yoshinagana ithas been observed that (")-spathunelol is an artefact formed
from (")-ent-bicyclogermacrane, when it is allowed to standat room temperature or during the extraction of liverworts.338
A total synthesis of (+)-ledol has been described.339 Stereo-selective total syntheses of (+)-aromadendrane and (")-alloaromadendrane have been achieved.340 The biomimeticsynthesis and absolute configuration of (")-tanzanene havebeen reported.341 The ozonolysis of (+)-aromadendrane andother terpenoids have been investigated.342 The rearrange-ments of ledene and aromadendrene in superacidic media havebeen studied.343 On the other hand, the rearrangement of(+)-ledene epoxide in acid medium has been described.344
21 PinguisaneTwo novel pinguisane derivatives 341 and 342 have beenobtained from the liverwort Dicranolejeunea yoshinagana.345
Another three new sesquiterpenes of this type 343–345 have
been isolated from axenic cultures of Aneura pinguis.346 Thestructure and biosynthesis of several pinguisane sesquiterpeneshave been reported.347 A novel pinguisanoic acid 346 has been
found in an extract of the liverwort Porella platyphylla.348 Inthis work the stereochemistry of â-pinguisenediol has beenrevised to 347. Known pinguisane sesquiterpenes have been
O
OGlcO
R
O
OR2O
O
O
OR1
OAcH
AcO
AcO
326 R1 = H; R2 = Glc327 R1 = Glc; R2 = H
328
324 R = α-Me325 R = β-Me
O
O
OHH
HO
RO
OAc
329 R = H330 R = Ang
HO OR
H
O
O
331 R = various
O
HO
O
OH
H
NCS
H
332 333 334
335 R1 = R2 = H336 R1 = H; R2 = Ac337 R1 = R2 = Ac
338
339 340
H
R1OAcO
H
O
AcO
H
AcO
H
H
HO
AcO
HO
O
OH
R2O
OR
OO
O
OO
O
OR
341 R = CHO342 R = CH2OAc
343 R = H344 R = Me
345
O
MeO2C OHOH
OH346 347
Fraga: Natural sesquiterpenoids 87
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obtained from another species of this genus, Porella verni-cosa.63 A racemic synthesis of â-pinguisene and pinguisenolhas been described.349
22 Miscellaneous sesquiterpenoidsThe myltaylane derivative 348 has been found in the liverwortBazzania trilobata.125 Benkarlaol 349 is a new sesquiterpenewith a new skeleton, which has been isolated from a Chinesered alga Laurencia karlae.350 Rarisetenolide 350, epoxyrarise-tenolide 351 and epirarisetenolide 352 are new sesquiterpenelactones with a new carbon framework, which have beenobtained from the marine ciliated morphospecies Euplotes
rariseta. These compounds are used by this organism asdefensive agents.351 The novel antifouling sesquiterpenes iso-cyanotrachyopsane 353 and 10-epi-axoisonitride 354 have beenfound in a nudibranch of the family Phyllidiidae.84 Theantiinflammatory and antipyretic activities of the sesquiter-pene spartidienedione have been studied.352 Dimeric sesquiter-pene thioalkaloids have been shown to have potent immuno-suppressive properties.353 An HPLC method for the separationof bilobalide and ginkgolides has been described.354
(")-Furodysinin has been synthesized in enantiomeric355
and racemic356 forms. Syntheses of ent-herbasolide357 (&)-2-pupukeanone358 and tavacpallescencin359 have been reported.
23 References1 E. Palomino, C. Maldonado, M. B. Kempff and M. B. Ksebati,J. Nat. Prod., 1996, 59, 77.
2 F. Jeske, S. Huneck and J. Jakupovic, Phytochemistry, 1996, 41,1539.
3 A. S. R. Anjaneyulu, N. S. K. Rao and M. J. R. V. Venugopal,Indian J. Chem., Sect. B, 1996, 35, 1001.
4 G. Pozzi, V. Birault, B. Werner, O. Dannenmuller, Y, Nakatani,G. Ourisson and S. Terakawa, Angew. Chem., Int. Ed. Engl., 1996,35, 177.
5 E. J. Graziani, R. J. Andersen, P. J. Krug and D. J. Faulkner,Tetrahedron, 1996, 52, 6869.
6 M. Miyazawa, H. Nankai and H. Kameoka, Phytochemistry,1996, 41, 105.
7 J. Donath and W. Bolands, Phytochemistry, 1995, 39, 785.8 R. Sekizawa, H. Iinuma, Y. Muraoka, H. Naganawa, N.Kinoshita, H. Nakamura, M. Hamada, T. Takeuchi and K.Umezawa, J. Nat. Prod., 1996, 59, 232.
9 J. M. Dolence and C. D. Poulter, Proc. Natl. Acad. Sci. USA,1995, 92, 5008.
10 Y. Q. Mu, C. A. Omer and R. A. Gibb, J. Am. Chem. Soc., 1996,118, 1817.
11 M. Lamothe, D. Perrin, D. Blotiéres, M. Leborgne, S. Gras, D.Bonnet, B. T. Hill and S. Halazy, Bioorg. Med. Chem. Lett., 1996,6, 1291.
12 S. B. Singh, R. G. Ball, G. F. Bills, C. Cascales, J. B. Gibbs,M. A. Goetz, K. Hoogsteen, R. G. Jenkins, J. M. Liesch, R. B.Lingham, K. C. Silverman and D. L. Zink, J. Org. Chem., 1996,61, 7727.
13 G. L. Kad, J. Kaur, S. Nayyar and J. Singh, Indian J. Chem., Sect.B, 1996, 35, 832.
14 S. Fielder, D. D. Rowan and M. S. Sherburn, Synlett, 1996, 349.15 D. H. Williams and D. J. Faulkner, Tetrahedron, 1996, 52, 4245.16 K. Matsuo, T. Arase, S. Ishida and Y. Sakaguchi, Heterocycles,
1996, 43, 1287.17 M. A. Brimble, D. D. Rowan and J. A. Spicer, Synthesis, 1996,
116.18 J. M. Dolence and C. D. Poulter, Tetrahedron, 1996, 52, 119.19 Y. Q. Mu, R. A. Gibbs, L. M. Eubanks and C. D. Poulter, J. Org.
Chem., 1996, 61, 8010.20 I. Gaon, T. C. Turek, V. A. Weller, R. L. Edelstein, S. K. Singh
and M. D. Distefano, J. Org. Chem., 1996, 61, 7738.21 H. Weng, C. Scarlata and H. D. Roth, J. Am. Chem. Soc., 1996,
118, 10 947.22 A. F. Barrero, J. Altarejos, E. J. Alvarez-Manzaneda, J. M.
Ramos and S. Salido, J. Org. Chem., 1996, 61, 2215.23 H. Tanimoto and T. Oritani, Tetrahedron: Asymmetry, 1996, 7,
1695.24 F. Nagashima, H. Izumo, A. Ishmaru, S. Momasaki, M. Toyota,
T. Hashimoto and Y. Asakawa, Phytochemistry, 1996, 41, 1285.25 J. A. Marco, J. F. Sanz-Cervera, M. D. Morante, V. García-Lliso,
J. Valles-Xirau and J. Jakupovic, Phytochemistry, 1996, 41, 837.26 C. Perez, J. M. Trujillo, L. N. Almonacid, E. Navarro and S. J.
Alonso, Nat. Prod. Lett., 1996, 8, 1.27 C. Perez, J. M. Trujillo, L. N. Almonacid, E. Navarro and S. J.
Alonso, J. Nat. Prod., 1996, 59, 69.28 K. Machida and M. Kikuchi, Phytochemistry, 1996, 41, 1333.29 A. K. Chakravarty, B. Das, K. Masuda and H. Ageta, Chem.
Pharm. Bull., 1996, 44, 1421.30 T. Kiyotani, K. Masuda, H. Ageta, A. K. Chakravarty and B.
Das, Acta Crystallogr., Sect. C, 1996, 52, 3216.31 H. Kijima, H. Otsuka, T. Ide, C. Ogimi, E. Hirata, A. Takushi
and Y. Takeda, Phytochemistry, 1996, 42, 723.32 H. Dietz and P. Winterhalter, Phytochemistry, 1996, 42, 1005.33 N. De Tommasi, S. Piacente, F. de Simone and C. Pizza, J. Agric.
Food Chem., 1996, 44, 1676.34 M. della Greca, A. Fiorentino, P. Monaco, L. Previtera and A.
Zarrelli, Nat. Prod. Lett., 1996, 8, 83.35 R. Baltenweck-Guyot, J. M. Trendel, P. Albrecht and A.
Schaeffer, Phytochemistry, 1996, 43, 621.36 M. Yoshikawa, Y. Fukuda, T. Taniyama and I. Kitagawa, Chem.
Pharm. Bull., 1996, 44, 41.37 A. Yajima, H. Takikawa and K. Mori, Liebigs Ann., 1996, 891.38 M. Tori, T. Hamagucha, K. Sagawa, M. Sono and Y. Asakawa,
J. Org. Chem., 1996, 61, 5362.39 Y. I. M. Nilsson, A. Aranyos, P. G. Andersson, J.-E. Båckvall,
J. L. Parrain, C. Ploteau and J. P. Quintard, J. Org. Chem., 1996,61, 1825.
40 B. M. Trost and Y. Li, J. Am. Chem. Soc., 1996, 118, 6625.41 O. Irie, Y. Fujiwara, H. Nemoto and K. Shishido, Tetrahedron
Lett., 1996, 37, 9229.42 D. F. Taber, R. P. Meagley and D. J. Doren, J. Org. Chem., 1996,
61, 5723.43 G. Vidari, G. Lanfranchi, F. Masciaga and J. D. Moriggi,
Tetrahedron: Asymmetry, 1996, 7, 3009.44 F. W. J. Demnitz and R. A. Raphael, Synthesis, 1996, 1305.45 F. Ferreres, P. Andrade and F. A. Tomás-Barberán, J. Agric.
Food Chem., 1996, 44, 2053.46 H. Yamamoto, T. Sugiyama and T. Oritani, Biosci., Biotechnol.,
Biochem., 1996, 60, 750.47 P. A. Rose, B. Lei, A. C. Shaw, D. L. Barton, M. K. Walker-
Simmons and S. R. Abrams, Phytochemistry, 1996, 41, 1251.48 R. D. Hill, J. H. Liu, D. Durnin, N. Lamb, A. Shawn and S. R.
Abraham, Plant Physiol., 1995, 108, 573.49 W. F. Fleck, B. Schlegel, P. Hoffmann, M. Ritzau, S. Heinze and
U. Graefe, J. Nat. Prod., 1996, 59, 780.50 Y. Uosaki, M. Yoshida, T. Ogawa and Y. Saitoh, J. Antibiot.,
1996, 49, 6.51 S. Grabley, R. Thiericke, M. Zerlin, A. Gohrt, S. Phillipps and A.
Zeeck, J. Antibiot., 1996, 49, 593.52 M. A. Hayes, S. K. Wrigley, I. Chetland, E. E. Reynolds, A. M.
Ainsworth, D. V. Renno, M. A. Latif, X. M. Cheng and D. J.Hupe, J. Antibiot., 1996, 49, 505.
53 V. Amstrong, M. Cortés and J. López, Nat. Prod. Lett., 1996, 8,225.
O
OH
H
OH
OH
CN
CN
O
OH
H
348 349
352 353 354
350351 11β,12-epoxy
1112
88 Natural Product Reports, 1998
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.rsc
.org
| do
i:10.
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/A81
5073
Y
View Online
54 M. Pulici, F. Sugawara, H. Koshino, J. Usawa, S. Yoshida, E.Lobkovsky and J. Clardy, J. Nat. Prod., 1996, 59, 47.
55 K. Siems, F. Weigt and E. Wollenweber, Phytochemistry, 1996,41, 1119.
56 M. Chu, R. Mierzwa, I. Truumees, A. King, M. Patel, J.Pichardo, A. Hart, B. Damahapatra, P. R. Das and M. S. Puar,Tetrahedron Lett., 1996, 37, 3943.
57 K. Torigoe, N. Wakasugi, N. Sakaizumi, T. Ikejima, H. Suzuki,K. Korjori and H. Suda, J. Antibiot., 1996, 49, 314.
58 M. Nakamura, Y. Ito, K. Ogawa, Y. Michisuji, S. I. Sato, M.Takada, M. Hayashi, S. Yaginuma, S. Yamamoto, K. Furihata,K. Shin-ya and H. Seto, J. Antibiot., 1995, 48, 1389.
59 B. E. Roggo, P. Hug, S. Moss, A. Staempfli, H. P. Kriemler andH. H. Peter, J. Antibiot., 1996, 49, 374.
60 S. Yaginuma and S. Ishikawa, Jpn. Kokai Tokkyo Koho JP07,330,622 [95,330,622] (Chem. Abstr., 1995, 124, 200 280).
61 S. Stefanelli, F. Sponga, P. Ferrari, C. Sottani, E. Corti, C.Brunati and K. Islam, J. Antibiot., 1996, 49, 611.
62 N. B. Perry, L. M. Foseter and S. D. Lorimer, Phytochemistry,1996, 41, 1201.
63 K. Ono, T. Sakamoto, H. Tanaka and Y. Asakawa, FlavourFragrance, 1996, 11, 53.
64 K. Kurata, K. Taniguchi and M. Suzuki, Phytochemistry, 1996,41, 749.
65 S. Urban and R. J. Capon, Aust. J. Chem., 1996, 49, 611.66 A. Montagnac, M. T. Martin, C. Debitus and M. Païs, J. Nat.
Prod., 1996, 59, 866.67 A. Aiello, E. Fattorusso, M. L. Menna and M. Pansini, Biochem.
Syst. Ecol., 1996, 24, 37.68 S. Urban and R. Capon, J. Nat. Prod., 1996, 59, 900.69 M. L. Bourguet-Kondracki, C. Debitus and M. Guyot, Tetra-
hedron Lett., 1996, 37, 3861.70 B. M. Trost, F. J. Fleitz and W. J. Watkins, J. Am. Chem. Soc.,
1996, 118, 5146.71 R. N. Saicic and S. Z. Zard, Chem. Commun., 1996, 1631.72 J. An and D. F. Wiemer, J. Org. Chem., 1996, 61, 8775.73 E. P. Locke and S. M. Hecht, Chem. Commun., 1996, 2717.74 Y. Ueki, M. Itoh, T. Katoh and S. Terashima, Tetrahedron Lett.,
1996, 37, 5719.75 E. I. Graziani and R. J. Andersen, J. Am. Chem. Soc., 1996, 118,
4701.76 T. A. Engler, M. H. Ali and F. Takusagawa, J. Org. Chem., 1996,
61, 8456.77 G. Erkel, U. Becker, T. Anke and O. Sterner, J. Antibiot., 1996,
49, 1189.78 H. Chen, Y. Zhu, X. M. Shen and Z. J. Jia, J. Nat. Prod., 1996,
59, 1117.79 M. Bruno, M. L. Bondi, M. P. Paternostro, N. A. Arnold, J. G.
Diaz and W. Herz, Phytochemistry, 1996, 42, 737.80 L. G. Cool, Phytochemistry, 1996, 41, 1015.81 G. Rücker, E. P. Schenkel, D. Manns, R. Mayer, K. Heiden and
B. M. Heinzmann, Planta Med., 1996, 62, 565.82 L. O. A. Manguro, K. M. Mukonyi and J. K. Githiomi, Planta
Med., 1996, 62, 84.83 Y. H. Kuo and M. T. Yu, Chem. Pharm. Bull., 1996, 44, 2150.84 T. Okino, E. Yoshimura, H. Hirota and N. Fusetani, Tetra-
hedron, 1996, 52, 9447.85 M. L. Sharma and T. Chand, Tetrahedron Lett., 1996, 37, 2279.86 F. Yuste, H. Barrios, E. Diaz, R. G. Henríquez, L. González-
Gutiérrez, B. Ortiz, R. Sánchez-Obregón and F. Walls, Nat. Prod.Lett., 1996, 8, 181.
87 T. Alpha, P. Raharivelomanana, J. P. Bianchini, R. Faure, A.Cambon and L. Joncheray, Phytochemistry, 1996, 41, 829.
88 P. M. F. M. Bastiaansen, J. B. P. A. Wijnberg and A. de Groot,J. Org. Chem., 1996, 61, 4955.
89 A. Iida, K. Konishi, H. Kubo, K. Tomioka, H. Tokuda and H.Nishino, Tetrahedron Lett., 1996, 37, 9219.
90 B. B. Jarvis, S. Wang and H. L. Ammond, J. Nat. Prod., 1996, 59,254.
91 L. O. Zamir, A. Nikolakikis, K. A. Devor and F. Sauriol, J. Biol.Chem., 1996, 271, 27 353.
92 D. E. Cane and Q. Xue, J. Am. Chem. Soc., 1996, 118, 1563.93 M. Zook, K. Johnson, T. Hohn and R. Hammerschmidt, Phyto-
chemistry, 1996, 43, 1235.94 W. A. König, A. Rieck, Y. Saritas, I. H. Hardt and K. H.
Kubeczka, Phytochemistry, 1996, 42, 461.95 A. Abad, C. Agulló, M. Arnó, A. C. Cunat, M. T. García and
R. J. Zaragoza, J. Org. Chem., 1996, 61, 5916.96 M. S. Buchanan, J. D. Connolly and D. S. Rycroft, Phytochem-
istry, 1996, 43, 1245.
97 Y. Fukuyama, Y. Kiriyama and M. Kodama, Tetrahedron Lett.,1996, 37, 1261.
98 T. Eicher, F. Servet and A. Speicher, Synthesis, 1996, 863.99 A. Srikrishna, T. J. Reddy, P. P. Kumar and D. Vijaykumar,
Synlett, 1996, 67.100 H. Nemoto, H. Hakamata, N. Nakamochi and K. Fukumoto,
Heterocycles, 1994, 39, 467.101 A. Nath, J. Mal and R. V. Venkasteswaran, J. Org. Chem., 1996,
61, 4391.102 M. S. Buchanan, J. D. Connolly, A. A. Kadir and D. S. Rycroft,
Phytochemistry, 1996, 42, 1641.103 Y. J. Chen, C. H. Wang and W. Y. Lin, Tetrahedron, 1996, 52,
13 181.104 N. N. Nazhimitdinova, A. I. Saidkhodzhaev and V. M. Malikov,
Khim. Prir. Soedin., 1995, 369; Chem. Nat. Compd. (Engl.Transl.), 1996, 31, 309.
105 S. N. Garg, S. K. Agarwal and S. Kumar, J. Med. Aromat. PlantSci., 1996, 18, 7, (Chem Abstr., 1996, 125, 81 941).
106 K. Nawamaki and M. Kuroyanagi, Phytochemistry, 1996, 43,1175.
107 Y. H. Kuo and L. L. Shiu, Chem. Pharm. Bull., 1996, 44, 1758.108 J. M. Fang, Y. C. Chen, B. W. Wang and Y. S. Cheng,
Phytochemistry, 1996, 41, 1361.109 A. F. Barrero, E. Alvarez-Manzaneda and A. Lara, Tetrahedron
Lett., 1996, 37, 3757.110 B. M. Fraga, R. Guillermo, J. R. Hanson and A. Truneh,
Phytochemistry, 1996, 42, 1583.111 Y. J. Chen and W. H. Chang, J. Org. Chem., 1996, 61, 2536.112 S. Das, A. Pal and D. Mukherjee, Tetrahedron Lett., 1996, 37,
4421.113 P. Weyerstahl, H. Marschall, C. Christiansen and I. Seelmann,
Liebigs Ann., 1996, 1641.114 H. Jianmei and Y. Chunshu, Phytochemistry, 1996, 42, 1375.115 T. Nakamura, E. Okuyama and M. Yamazaki, Chem. Pharm.
Bull., 1996, 44, 1908.116 C. L. Queiroga, V. L. Ferracini and A. J. Marsaioli, Phytochem-
istry, 1996, 42, 1097.117 T. Hieda, M. Tazaki, Y. Morishita, T. Aoki and S. Nagahama,
Phytochemistry, 1996, 42, 159.118 S. Zapf, A. Wunder, T. Anke, D. Klostermeyer, W. Steglich, R.
Shan, O. Sterner and W. Scheuer, Z. Naturforsch., Teil C, 1996,51, 487.
119 S. Zapf, A. Wunder, T. Anke, D. Klostermeyer, W. Steglich, R.Shan, O. Sterner and W. Scheuer, Z. Naturforsch., Teil C, 1996,51, 493.
120 J. P. Kim, W. G. Kim, H. Koshino, J. Jung and I. D. Yoo,Phytochemistry, 1996, 41, 425.
121 J. P. Kim, W. G. Kim, J. H. Park, J. Jung, H. Koshino and I. D.Yoo, Korean J. Pharmacogn., 1996, 27, 26.
122 I. Kubo, S. K. Chaudhuri, Y. Kubo, Y. Sanchez, T. Ogura, T.Saito, H. Ishikawa and H. Haraguchi, Planta Med., 1996, 62, 427.
123 E. S. Barreira, F. J. Queiros-Monte and R. Braz-Filho, Nat. Prod.Lett., 1996, 8, 285.
124 H. Otsuka, M. Yao, E. Hirata, A. Takushi and Y. Takeda,Phytochemistry, 1996, 41, 1351.
125 F. Nagashima, S. Momosaki, Y. Watanabe, S. Takaoka, S.Huneck and Y. Asakawa, Phytochemistry, 1996, 42, 1361.
126 G. D. Davis, M. Essenberg, K. D. Berlin, R. Faure and E. M.Gaydou, Magn. Reson. Chem., 1996, 34, 156.
127 E. M. Davis, J. Tsuji, G. D. Davis, M. L. Pierce and M.Essenberg, Phytochemistry, 1996, 41, 1047.
128 X. Y. Chen, M. Wang, Y. Chen, V. J. Davisson and P. Heinstein,J. Nat. Prod., 1996, 59, 944.
129 D. F. Taber, T. E. Christos and C. N. Hodge, J. Org. Chem.,1996, 61, 2081.
130 B. Ye, H. Nakamura and A. Murai, Tetrahedron, 1996, 52, 6361.131 R. M. Letcher and C. F. Lee, J. Chem. Res. (S), 1996, 347.132 L. F. Tietze and T. Raschke, Liebigs Ann., 1996, 1981.133 A. I. Meyers and J. J. Willemsen, Tetrahedron Lett., 1996, 37, 791.134 G. Riesch, E. Urban and H. Vollenkle, Tetrahedron, 1996, 52,
8725.135 S. Bharel, A. Gulati, M. Z. Abdin, P. S. Srivastava and S. K. Jain,
Fitoterapia, 1996, 67, 387.136 M. Bordoloi, N. C. Barua and A. C. Ghosh, Phytochemistry,
1996, 41, 557.137 S. U. Kim, J. Han and Y. Lim, Planta Med., 1996, 62, 480.138 A. K. Pathak, D. C. Jain and J. P. Sharma, Indian J. Chem., Sect.
B, 1995, 34, 992.139 A. C. Beekman, H. J. Woerdenbag, H. H. Kampinga and
A. W. T. Konings, Phytotherapy Res., 1996, 10, 140.
Fraga: Natural sesquiterpenoids 89
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140 S. U. Kim and H. J. Kwon, Planta Med., 1996, 62, 359.141 D. C. Jain, A. K. Mathur, M. M. Gupta, A. K. Singh, R. K.
Verma, A. P. Gupta and S. Kumar, Phytochemistry, 1996, 43,993.
142 M. M. Gupta, D. C. Jain, A. K. Mathur, A. K. Singh, R. K.Verma and S. Kumar, Planta Med, 1996, 62, 280.
143 J. F. S. Ferreira and J. Janick, Phytochemistry, 1996, 41, 97.144 W. M. Wu, Z. J. Yao, Y. L. Wu, K. Jiang, Y. F. Wang, H. B.
Chen, F. Shan and Y. Li, Chem. Commun., 1996, 2213.145 R. C. Haynes and S. C. Vonwiller, Tetrahedron Lett., 1996, 37,
253.146 R. C. Haynes and S. C. Vonwiller, Tetrahedron Lett., 1996, 37,
257.147 E. A. Abourashed and C. D. Hufford, J. Nat. Prod., 1996, 59, 251.148 M. G. Constantino, M. Beltrame and G. V. J. de Silva, Synth.
Commun., 1996, 26, 321.149 H. J. Liu and W. L. Yeh, Heterocycles, 1996, 42, 493.150 M. A. Avery, J. D. Bonk and J. Bupp, J. Labelled Compd.
Radiopharm., 1996, 38, 263.151 A. M. Galal, M. S. Ahmad, F. S. El-Feraly and A. T. McPhail,
J. Nat. Prod., 1996, 59, 917.152 M. Jung and B. H. Youn, Heterocycles, 1996, 43, 1587.153 M. Schwaebe and R. D. Little, J. Org. Chem., 1996, 61, 3240.154 W. M. Daniewski, W. Anczewski, M. Gumulka, W. Danikiewic,
U. Jacobsson and T. Norin, Phytochemistry, 1996, 43, 811.155 W. Shi and G. Q. Han, J. Chin. Pharm. Sci., 1996, 5, 63.156 M. Ihara, K. Makita, Y. Fujiwara, Y. Tokunaga and K.
Fukumoto, J. Org. Chem., 1996, 61, 6416.157 P. Tane, J. F. Ayafor, L. J. Farrugia, J. D. Connolly, D. S.
Rycroft and F. Tillequin, Nat. Prod. Lett., 1996, 9, 39.158 J. G. C. Hamilton, G. W. Dawson and J. A. Pickett, J. Chem.
Ecol., 1996, 22, 2331.159 A. Chaironi, C. Riche, E. Lassaba and A. Benharref, Acta
Crystallogr., Sect. C, 1996, 52, 3240.160 M. Yoshikawa, H. Shimada, H. Matsuda, J. Yamahara and N.
Murakami, Chem. Pharm. Bull., 1996, 44, 1656.161 U. Kastner, J. Jurenitsch, S. Glasi, B. Follrich, A. Gacanelli, M.
Schroder, M. Schubert-Zsilavecz, W. Schmidt, E. Haslinger andW. Kubelka, Pharmazie, 1996, 51, 503.
162 L. U. Román, L. G. Zepeda, N. R. Morales, S. Flore, J. D.Hernández, C. M. Cerda-García-Rojas and P. Joseph-Nathan,J. Nat. Prod., 1996, 59, 391.
163 P. Joseph-Nathan, M. Meléndez-Rodríguez, C. M. Cerda-García-Rojas and C. A. N. Catalán, Tetrahedron Lett., 1996, 37, 8093.
164 M. Alam, E. B. G. Jones, M. B. Hossaain and D. van der Helm,J. Nat. Prod., 1996, 59, 454.
165 M. Pulici, F. Sugawara, H. Koshino, J. Uzawa, S. Yoshida, E.Lobkovsky and J. Clardy, J. Org. Chem., 1996, 61, 2122.
166 A. B. de Oliveira, D. A. Saude, K. S. P. Perry, D. S. Duarte, D. S.Raslan, M. A. D. Boaventura and E. Chiari, Phytotherapy Res.,1996, 10, 292.
167 W. Y. Tsui and G. Brown, J. Chem. Soc., Perkin Trans. 1, 1996,2507.
168 I. G. Collado, J. R. Hanson and A. J. Macías-Sánchez, Tetra-hedron, 1996, 52, 7961.
169 Y. Tambe, H. Tsujiuchi, G. Honda, Y. Ikeshiro and S. Tanaka,Planta Med., 1996, 62, 469.
170 W. T. Tsui and G. D. Brown, J. Nat. Prod., 1996, 59, 1084.171 I. G. Collado, R. Hernández-Galán, V. Prieto, J. R. Hanson and
L. G. Rebordinos, Phytochemistry, 1996, 41, 513.172 L. Rebordinos, J. M. Cantoral, M. V. Prieto, J. R. Hanson and G.
Collado, Phytochemistry, 1996, 42, 383.173 A. I. Meyers, S. Bienz, H. B. Kwon and R. H. Wallace, Helv.
Chim. Acta, 1996, 79, 1026.174 P. Weyerstahl, H. Marschall, M. Schulze and I. Schwope, Liebigs
Ann., 1996, 799.175 H. R. Bokesch, T. C. McKee, J. H. Cardellina II and M. R. Boyd,
Tetrahedron Lett., 1996, 37, 3259.176 F. Almassi, E. L. Ghisalberti, B. W. Skelton and A. H. White,
J. Nat. Prod., 1996, 59, 59.177 M. Pulici, F. Sugawara, H. Koshino, J. Usawa and S. Yoshida,
J. Chem. Res. (S), 1996, 378.178 G. Mehta and D. S. Reddy, Synlett, 1996, 229.179 M. Hatanaka, F. Ueno and I. Ueda, Tetrahedron Lett., 1996, 37,
89.180 W. R. Abraham and D. Abate, Z. Naturforsch., Teil C, 1995, 50,
748.181 C. Baralotto, M. Chanon and M. Julliard, J. Org. Chem., 1996,
61, 3576.
182 D. J. L. Clive, S. R. Magnuson, H. W. Manning and D. L.Mayhew, J. Org. Chem., 1996, 61, 2095.
183 E. J. Enholm and Z. J. Jia, Chem. Commun., 1996, 1567.184 E. J. Enholm and Z. J. Jia, Tetrahedron Lett., 1996, 37, 1177.185 J. Zhang and X. Z. Feng, Chin. Chem. Lett., 1996, 7, 1097.186 W. M. Daniewski, M. Gomulka, D. Truszewska, W. Anczewski,
E. Bloszyk, B. Drozdz, U. Jacobsson and T. Norin, Pol. J. Chem.,1995, 69, 1687.
187 P. Gluzinski, W. M. Daniewski and M. Gomulka, Pol. J. Chem.,1996, 70, 60.
188 W. M. Daniewski, M. Gomulka, U. Jacobsson and T. Norin,Phytochemistry, 1996, 41, 1093.
189 M. Jonassohn, O. Sterner and H. Anke, Tetrahedron, 1996, 52,1473.
190 A. Fürstner and K. Langemann, J. Org. Chem., 1996, 61, 8746.191 K. Tanaka and K. Ogasawara, Chem. Commun., 1996, 1839.192 T. Ohshima, K. Kagechika, M. Adachi, M. Sodeoka and M.
Shibasaki, J. Am. Chem. Soc., 1996, 118, 7108.193 A. Wunder, T. Anke, D. Klostermeyer and W. Steglich,
Z. Naturforsch., Teil C, 1996, 51, 493.194 I. K. Lee, C. Y. Jeong, S. M. Cho, G. S. Yun, Y. S. Kim, S. H.
Yu, H. Koshino and I. D. Yoo, J. Antibiot., 1996, 49, 821.195 F. R. Kinder Jr., R. M. Wang, W. E. Bauta and K. W. Bair,
Bioorg. Med. Chem. Lett., 1996, 6, 1029.196 T. G. McCloud, P. A. Klueh, K. C. Pearl, L. K. Cartner and
G. M. Muschik, Nat. Prod. Lett., 1996, 9, 87.197 T. C. McMorris, M. J. Kelner, W. Wang, J. Yu, L. A. Estes and
R. Taetle, J. Nat. Prod., 1996, 59, 896.198 R. Farrell, F. Kelleher and H. Sheridan, J. Nat. Prod., 1996, 59,
446.199 A. Padwa, E. A. Curtis and V. P. Sandanayaka, J. Org. Chem.,
1996, 61, 73.200 M. Tori, K. Nakashima, T. Takeda, Y. Kan, S. Takaoka and Y.
Asakawa, Tetrahedron, 1996, 52, 6339.201 A. S. R. Anjaneyulu, G. V. Rao and N. S. K. Rao, Indian J.
Chem., Sect. B, 1996, 35, 815.202 A. Mayer, B. Köpke, H. Anke and O. Sterner, Phytochemistry,
1996, 41, 375.203 J. G. C. Hamilton, G. W. Dawson and J. A. Pickett, J. Chem.
Ecol., 1996, 22, 1477.204 M. B. Bykhovskaja and B. S. Zhorov, J. Chem. Ecol., 1996, 22,
869.205 W. A. König, N. Bülow, C. Fricke, S. Melching, A. Rieck and H.
Muhle, Phytochemistry, 1996, 43, 629.206 V. N. Zhabinskii, A. J. Minnaard, J. B. P. A. Wijnberg and A. de
Groot, J. Org. Chem., 1996, 61, 4022.207 M. N. Kobilov, A. I. Saidkhodzhaev and N. D. Abdullaev, Khim.
Prir. Soedin., 1995, 627; Chem. Nat. Compd. (Engl. Transl.),1996, 31, 530.
208 K. S. Chen, F. R. Chang, T. T. Jong and Y. C. Wu, J. Nat. Prod.,1996, 59, 704.
209 D. E. Cane and Y. S. Tsantrizos, J. Am. Chem. Soc., 1996, 118,10 037.
210 D. P. Piet, M. C. R. Franssen and A. de Groot, Tetrahedron,1996, 52, 11 273.
211 E. A. Sattar, A. M. Galal and G. S. Mossa, J. Nat. Prod., 1996,59, 403.
212 S. R. Rojatkar, S. S. Pawar, P. P. Pujar, D. D. Sawaikar, S.Gurunath, V. T. Sathe and B. A. Nagasampagi, Phytochemistry,1996, 41, 1105.
213 Y. L. Lin, J. C. Ou, Y. H. Kuo, J. K. Lin and K. H. Lee, J. Nat.Prod., 1996, 59, 991.
214 S. Borkosky, D. Alvarez-Valdés, A. Bardón, J. G. Diaz and W.Herz, Phytochemistry, 1996, 42, 1637.
215 P. P. H. But, P. M. Kon, H. Cao and C. T. Che, Planta Med.,1996, 62, 474.
216 A. Bardón, L. Cardona, C. A. N. Catalán and J. R. Pedro,Phytochemistry, 1996, 41, 845.
217 B. García, H. Skaltsa, F. I. Navarro, J. R. Pedro and D. Lazart,Phytochemistry, 1996, 41, 1113.
218 L. R. Hernández, E. C. de Riscala, C. A. N. Catalán, J. G. Diazand W. Herz, Phytochemistry, 1996, 42, 681.
219 L. R. Hernández, C. A. N. Catalán, C. M. Cerda-García-Rojasand P. Joseph-Nathan, Phytochemistry, 1996, 42, 1369.
220 T. Morgenstern, R. M. King and J. Jakupovic, Phytochemistry,1996, 41, 1543.
221 K. Matsunaga, M. Saitoh and Y. Ohizumi, Tetrahedron Lett.,1996, 37, 1455.
222 C. A. N. Catalán, S. A. Borkosky and P. Joseph-Nathan,Biochem. Syst. Ecol., 1996, 24, 659.
90 Natural Product Reports, 1998
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223 G. François, C. M. Passreiter, H. J. Woerdenbag and M. vanLooveren, Planta Med., 1996, 62, 126.
224 S. Montanaro, A. Bardón and C. A. N. Catalán, Fitoterapia,1996, 57, 185.
225 T. Lu and N. H. Fischer, Spectrosc. Lett., 1996, 29, 437.226 Y. C. Kim, V. das S. Bolzani, N. Baj, A. A. L. Gunatilaka and
D. G. I. Kingston, Planta Med., 1996, 62, 61.227 T. T. Edilkbaeva, K. M. Turdybekov, N. M. Gafurov, S. M.
Adekenov and Z. M. Muldakhmetov, Chem. Nat. Compd. (Engl.Transl.), 1996, 32, 39.
228 M. M. Afonso, H. Mancilla, J. A. Palenzuela and A. Galindo,Tetrahedron, 1996, 52, 11 827.
229 M. Bruno, M. P. Paternostro, T. E. Gedris and W. Herz,Phytochemistry, 1996, 41, 335.
230 S. L. Wu and W. S. Li, J. Chin. Chem. Soc. (Taipei), 1995, 42,555.
231 J. Su, S. Chen, L. Zeng, C. Zeng and H. Wu, Chin. Sci. Bull. 1996,41, 1877 (Chem. Abstr., 1996, 126, 87 252).
232 M. Toyota, E. Nakaishi and Y. Asakawa, Phytochemistry, 1996,41, 833.
233 A. Rieck and W. A. König, Phytochemistry, 1996, 43, 1055.234 Y. Lin, T. Lin, Z. Yuan, Z. Wu, J. Fang and Z. Huang,
Zhongshan Daxue Xuebao, Ziran Kexueban, 1996, 35, 75 (Chem.Abstr., 1996, 125, 279 487).
235 J. F. Hu, S. P. Bai and Z. J. Jia, Phytochemistry, 1996, 43, 815.236 J. F. Hu, Q. X. Zhu, S. P. Bai and Z. J. Jia, Planta Med., 1996, 62,
477.237 Y. M. Syah, E. L. Ghisalberti, B. W. Skelton and A. H. White,
Aust. J. Chem., 1996, 49, 707.238 S. Lin and J. Ding, Yunnan Zhiwu Yanjui, 1996, 18, 349 (Chem.
Abstr., 1996, 126, 101 758).239 Y. Zhao, J. M. Yue, J. K. Ding, Z. W. Lin and H. D. Sun, Chin.
Chem. Lett., 1996, 7, 1093.240 P. Raharivelomanana, J. P. Bianchini, R. Raure, A. Cambon and
M. Azzaro, Phytochemistry, 1996, 41, 243.241 C. C. Wang, C. S. Kuoh and T. S. Wu, J. Nat. Prod., 1996, 59,
409.242 T. Kato, B. Frei, M. Heinrich and O. Sticher, Planta Med., 1996,
62, 67.243 G. M. S. P. Gulhon and A. H. Müller, Phytochemistry, 1996, 41,
417.244 J. F. Hu, S. P. Bai and Z. J. Jia, Chin. Chem. Lett., 1996, 7, 913.245 N. Gören, Phytochemistry, 1996, 42, 747.246 G. T. Maatooq and J. J. Hofmann, Phytochemistry, 1996, 43, 67.247 G. T. Maatooq, D. K. Stumpf, J. J. Hoffmann, L. K. Hutter and
B. T. Timmermann, Phytochemistry, 1996, 41, 519.248 M. Nukina, T. Otuki, T. Kurebayashi, K. Hosokawa, M. Sekine,
S. Ito, M. Suenaga, A. Sato and T. Sassa, Tennen Yuki KagobutsoToronkai Koen Yoshishu, 1996, 391 (Chem. Abstr., 1996, 126,16 550).
249 A. A. Ahmed, B. A. Ali, M. Krawiec and W. H. Watson, ActaCrystallogr., Sect. C, 1996, 52, 235.
250 C. A. de Simone, M. O. F. Goulart, M. A. Pereira and J.Zukerman-Schpector, Acta Crystallogr., Sect. C, 1996, 52, 117.
251 B. S. M. Tenius, A. R. Rhode, M. M. Victor and C. Viegas,Synth. Commun., 1996, 26, 197.
252 Z. Xiong, J. Yang and Y. Li, Tetrahedron: Asymmetry, 1996, 7,2607.
253 G. Blay, L. Cardona, B. García, J. R. Pedro and J. J. Sánchez,Tetrahedron, 1996, 52, 10 507.
254 G. Blay, L. Cardona, B. García, C. L. García and J. R. Pedro,J. Org. Chem., 1996, 61, 3815.
255 A. K. Banerjee and J. A. Azocar, Monatsh. Chem., 1996, 127,1031.
256 A. Saito, A. Tanaka and T. Oritani, Tetrahedron: Asymmetry,1996, 7, 2923.
257 M. A. Wang, M. Wang, J. Liu, F. H. Chen and Q. F. Shen,Bopuxue Zazhi, 1995, 12, 567 (Chem. Abstr., 1995, 124, 201 818).
258 Y. H. Kuo, C. J. Chou, L. M. Y. Kuo, Y. Y. Hu, Y. C. Chen,C. F. Chen and K. H. Lee, Phytochemistry, 1996, 41, 549.
259 M. A. Wang and F. H. Chen, Gaodeng Xuexiao Huaxue Xuebao,1996, 17, 1250 (Chem. Abstr., 1996, 125, 163 298).
260 K. V. S. Sekar, J. M. Campagne and A. T. Sneden, Planta Med.,1996, 62, 368.
261 W. G. Zheng, R. X. Tan, L. Yang and Z. L. Liu, Spectrosc. Lett.,1996, 29, 1589.
262 D. Boriky, M. Berrada, M. Talbi, G. Keravis and F. Rouessac,Phytochemistry, 1996, 43, 309.
263 M. N. Todorova and M. L. Krasteva, Phytochemistry, 1996, 42,1231.
264 A. B. Trendafilova, M. N. Todorova and C. V. Gussev, Phyto-chemistry, 1996, 42, 469.
265 W. Y. Tsui and G. D. Brown, Phytochemistry, 1996, 41, 819.266 S. F. Farag, N. A. El-Emary and M. Niwa, Chem. Pharm. Bull.,
1996, 44, 661.267 N. Gören, H. J. Woerdenbag and C. Bozok-Johansson, Planta
Med., 1996, 62, 419.268 M. Ginanneschi, M. Chelli, A. M. Papini, D. Pinzani and G.
Rapi, Magn. Reson. Chem., 1996, 34, 95.269 T. Kawamata, N. Nagashima, R. Nakai and T. Tsuji, Synth.
Commun., 1996, 26, 139.270 I Fernández, J. R. Pedro and R. de la Salud, Tetrahedron, 1996,
52, 12 031.271 S. Gobbato and E. Lolla, Fitoterapia, 1996, 57, 159.272 A. Srikrishna and R. Viswajanani, Tetrahedron Lett., 1996, 37,
2863.273 A. Srikrishna and R. Viswajanani, Indian J. Chem., Sect. B, 1996,
35, 521.274 M. Tori, M. Ikawa, T. Sagawa, H. Furuta, M. Sono and Y.
Asakawa, Tetrahedron, 1996, 52, 9999.275 H. Hirota, Y. Tomono and N. Fusetani, Tetrahedron, 1996, 52,
2359.276 A. C. Guevel and D. J. Hart, J. Org. Chem., 1996, 61, 473.277 E. Piers and R. M. Oballa, J. Org. Chem., 1996, 61, 6439.278 M. C. Banwell and J. M. Cameron, Tetrahedron Lett., 1996, 37,
525.279 P. Weyerstahl, H. Marschall, U. Splittgerber and D. Wolf, Liebigs
Ann., 1996, 1195.280 H. Okugawa, R. Ueda, K. Matsumoto, K. Kawanishi and A.
Kato, Planta Med., 1996, 62, 2.281 M. T. Crimmins, Z. Wang and A. McKerlie, Tetrahedron Lett.,
1996, 37, 8703.282 Y. Takemoto, S. Karaoka, T. Ohra, Y. Yonetoka and C. Iwata,
Chem. Commun., 1996, 1655.283 H. J. Liu, C. L. Wu, T. Hashimoto and Y. Asakawa, Tetrahedron
Lett., 1996, 37, 9307.284 J. J. Gao, Z. J. Jia and C. Codina, Phytochemistry, 1996, 43, 1411.285 Y. Zhao, S. Parson, R. L. Baxter, Z. J. Jia, H. D. Sun and D. W. H.
Rankin, Chem. Commun., 1996, 2473.286 H. M. Chen, B. G. Wan and Z. J. Jia, Indian J. Chem., Sect. B,
1996, 35, 1304.287 A. L. Anaya, B. E. Hernández-Bautista, A. Torres-Barragán, J.
León-Cantero and M. Jiménez-Estrada, J. Chem. Ecol., 1996, 22,393.
288 M. Aguilar-Martínez, M. Jiménez-Estrada, N. A. Macías-Ruvalcaba and B. Lotina-Hennsen, J. Agric. Food Chem., 1996,44, 290.
289 Y. Yaoita and M. Kikuchi, Chem. Pharm. Bull., 1996, 44, 1731.290 Y. Yaoita and M. Kikuchi, Nat. Med., 1996, 50, 49.291 Y. Yaoita and M. Kikuchi, Phytochemistry, 1996, 42, 751.292 G. Delgado, P. E. García, R. I. Roldan, R. Bye and E. Linares,
Nat. Prod. Lett., 1996, 8, 145.293 H. M. Chen, M. S. Cai and J. Z. Jia, Chin. Chem. Lett., 1996, 7,
1100.294 M. J. Pestchanker, C. E. Tonn, P. C. Rossomando, O. S.
Giordano and E. Guerreiro, Nat. Prod. Lett., 1996, 8, 33.295 F. Nagashima, H. Tanaka and Y. Asakawa, Phytochemistry,
1996, 42, 93.296 O. Hamelin, J. P. Depres and A. E. Greene, J. Am. Chem. Soc.,
1996, 118, 9992.297 T. G. Back, P. L. Gladstone and M. Parvez, J. Org. Chem., 1996,
61, 3806.298 P. Weyerstahl, H. Marschall and G. Collin, Liebigs Ann., 1996,
99.299 N. H. Anh, H. Ripperger, T. V. Sung and G. Adam, Phytochem-
istry, 1996, 42, 1167.300 Y. Fukuyama, H. Minami, R. Ichikawa, K. Takeuchi and M.
Kodama, Phytochemistry, 1996, 42, 741.301 M. Tori, M. Yoshida, M. Yokohama and Y. Asakawa, Phyto-
chemistry, 1996, 41, 977.302 H. Achenbach, G. Benirschke and J. Lange, J. Nat. Prod., 1996,
59, 77.303 Y. Seo, J. R. Rho, N. Geum, J. B. Yoon and J. Shin, J. Nat.
Prod., 1996, 59, 985.304 A. A. Ahmed, M. A. Ela, A. Arias de Adams and T. Mabry,
Planta Med., 1996, 62, 385.305 I. A. Southwell and D. J. Tucker, J. Essent. Oil Res., 1996, 8, 143.306 K. A. El Sayed and M. T. Hamann, J. Nat. Prod., 1996, 59, 687.307 T. Koike, K. Yamazaki, M. Fukumoto, K. Yashiro, N. Takeuchi
and S. Tobinaga, Chem. Pharm. Bull., 1996, 44, 646.
Fraga: Natural sesquiterpenoids 91
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308 D. P. Piet, R. V. O. Orru, L. H. D. Jenniskens, C. van de Haar,T. A. van Beek, M. C. R. Franssen, J. B. P. A. Wijnberg andA. de Groot, Chem. Pharm. Bull., 1996, 44, 1400.
309 E. Lee and C. H. Yoon, Tetrahedron Lett., 1996, 37, 5929.310 B. M. Trost and R. I. Higuchi, J. Am. Chem. Soc., 1996, 118,
10 094.311 I. Merfort, G. Willuh, D. Wendisch and D. Gondol, Phytochem-
istry, 1996, 42, 1093.312 W. Kisiel and B. Barszcz, Phytochemistry, 1997, 43, 823.313 A. S. Al-Easa, A. B. M. Rizk and A. A. Ahmed, Phytochemistry,
1996, 43, 423.314 F. Menichini, R. di Benedetto and F. delle Monache, Phytochem-
istry, 1996, 41, 1377.315 N. Gören, E. Tahtasakal, M. Kraviec and W. H. Watson,
Phytochemistry, 1996, 42, 757.316 A. D. Rodríguez and A. Boulanger, J. Nat. Prod., 1996, 59, 653.317 M. J. Hewlett, M. J. Begley, W. A. Groenewegen, S. Heptinstall,
D. W. Knight, J. May, U. Salan and D. Toplis, J. Chem. Soc.,Perkin Trans. 1, 1996, 1979.
318 M. Todorova, A. Trendafilova and C. Gussev, Dokl. Bolg. Akad.Nauk., 1996, 49, 45.
319 A. M. Peters, N. Haagsma, K. H. Gensch and A. van Amerongen,J. Agric. Food Chem., 1996, 44, 3611.
320 J. Castaneda-Acosta, N. H. Fischer and F. R. Fronczek, ActaCrystallogr., Sect. C, 1996, 49, 1263.
321 G. Mattern, E. Weckert, D. Youssef and A. W. Frahm, ActaCrystallogr., Sect. C, 1996, 52, 1791.
322 D. Youssef and A. W. Frahm, Phytochemistry, 1996, 41, 1107.323 C. M. Passreiter, I. Merfort, C. Bestendonk, G. Willuhn and A.
Steigel, Planta Med., 1996, 62, 39.324 S. Piacente, C. Pizza, N. De Tommas and F. de Simone, Phyto-
chemistry, 1996, 41, 1357.325 J. H. Kim, S. J. Lee, Q. Lin, M. W. Bierner and T. J. Mabry,
Biochem. Syst. Ecol., 1996, 24, 795.326 E. M. Petenatti, M. J. Pestchanker, L. A. del Vitto and E.
Guerreiro, Phytochemistry, 1996, 42, 1367.327 K. A. Dzhazin, Y. V. Gatilov and S. M. Adekenov, Khim. Prir.
Soedin., 1995, 79; Chem. Nat. Compd. (Engl. Transl.), 1995, 31,63.
328 Q. Wang, B. N. Zhou, E. W. Zhang, Y. Y. Lin, L. Z. Lin, R. R.Gil and G. A. Cordell, Planta Med., 1996, 62, 166.
329 D. K. Pandey, J. Chem. Ecol., 1996, 22, 151.330 T. Money and M. K. C. Wong, Tetrahedron, 1996, 52, 6307.331 M. N. Todorova, E. T. Tsankova, A. B. Trendafilova and C. V.
Gussev, Phytochemistry, 1996, 41, 553.332 H. Monti, P. Charles and G. Leandri, Synth. Commun., 1996, 26,
4123.333 L. A. Paquette, C. F. Sturino, X. Wang, J. C. Prodger and D.
Koh, J. Am. Chem. Soc., 1996, 118, 5620.
334 S. J. Lin and C. L. Wu, Phytochemistry, 1996, 41, 1439.335 M. Toyota, I. Nakamura, S. Takaoka, Y. Kan and Y. Asakawa,
Phytochemistry, 1996, 41, 575.336 K. Nabeta, S. Ohkubo, R. Hozumi, T. Fukushi, H. Nakai and K.
Katoh, Phytochemistry, 1996, 43, 83.337 C. L. Wu, Y. M. Huang and J. R. Chen, Phytochemistry, 1996, 42,
677.338 M. Toyota, H. Koyama, M. Mizutani and Y. Azakawa, Phyto-
chemistry, 1996, 41, 1347.339 S. L. Gwaltney II and K. J. Shea, Tetrahedron Lett., 1996, 37, 949.340 T. Tanaka, K. Maeda, H. Mikamiyama, Y. Funakoshi, K.
Uenaka and C. Iwata, Tetrahedron, 1996, 52, 4257.341 S. K. Paknikar, K. P. Fondekar and R. Mayer, Nat. Prod. Lett.,
1996, 8, 253.342 K. Griesbaum, M. Hilß and J. Bosch, Tetrahedron, 1996, 52,
14 813.343 M. P. Polovinka, A. A. Shal’ko, D. V. Korchagina, Y. V. Gatilov,
V. V. Shcherbukhin and V. A. Barkhash, Tetrahedron Lett., 1996,37, 2631.
344 I. Bombarda, E. M. Gaydou, J. Smadja, C. Lageot and R. Faure,J. Agric. Food Chem., 1996, 44, 1840.
345 M. Toyota, H. Koyama, T. Hashimoto and Y. Asakawa, Chem.Pharm. Bull., 1995, 43, 714.
346 H. Tazaki, H. Soutome, K. Nabeta, H. Okuyama and H. Becker,Phytochemistry, 1996, 42, 465.
347 H. Tazaki, H. Soutome, F. Ishikawa, T. Iwasaki and K. Nabeta,Tennen Yuki Kagobutsu Toronkai Koen Yoshishu, 1996, 38, 97(Chem. Abstr., 1996, 126, 4638).
348 M. S. Buchanan, J. D. Connolly and D. S. Rycroft, Phytochem-istry, 1996, 43, 1249.
349 D. Schinzer and K. Ringe, Tetrahedron, 1996, 52, 7475.350 L. M. Zheng, Y. L. Zhong, J. Y. Su, H. M. Wu and K. Ma, Chin.
J. Chem., 1996, 14, 370.351 G. Guella, F. Dini and F. Pietra, Helv. Chim. Acta, 1996, 79,
2180.352 C. Delporte, N. Backhouse, R. Negrete, M. C. Gallardo and P.
Rivera, J. Pharmacogn., 1996, 34, 179.353 J. Yamahara, H. Shimoda, H. Matsuda and M. Yoshikawa, Biol.
Pharm. Bull., 1996, 19, 1241.354 J. T. B. Strode, L. T. Taylor and T. A. van Beek, J. Chromatogr.,
1996, 738, 115.355 T. L. Ho and R. J. Chein, Chem. Commun., 1996, 1147.356 A. M. Moiseenkov, A. V. Lozanova, A. A. Surkova and V. V.
Veselovsky, Mendeleev Commun., 1996, 89.357 T. L. Ho and F. S. Liang, Chem. Commun., 1996, 1887.358 N. C. Chang and C. K. Chang, J. Org. Chem.., 1996, 61, 4967.359 T. L. Ho and Y. J. Lin, J. Chin. Chem. Soc. (Taipei), 1996, 43,
207.
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