ii. M. R. Grimmett and K. H. R. Lim, Aust. J. Chem., 31, 689 (1978). 12. V. Papesch and R. M. Dodson, J. Org. Chem., 30, 199 (1965). 13. S. P. Mal'tseva, Z. A. Borodulina, and B. I. Stepanov, Zh. Org. Khim., 9, 815 (1973).

AMASS SPECTROSCOPIC STUDY OF 2-X-ETHOXY-4,6-DICHLORO-symm-TRIAZINES

L. A. Larionova,* A. B. Koshokov, K. A. V'yunov, O. A. Nikitin, A. A. Rodin, and A. I. Ginak

UDC 547.491.8'272'222'236'239:543.51

Defocusing and high resolution techniques were used to study the mass spectrometric decomposition of monoalkoxy-symm-triazines. Such decomposition was found to differ significantly from that of the corresponding dialkoxy and trialkoxy derivatives since, in addition to fragmentation of the side chain in various decomposition steps, de- composition of the heterocycle is also found with elimination of neutral CICN, CICNH', and HOCN fragments.

Dichloro derivatives of symm-triazines are starting materials for the synthesis of tri- substituted triazines with important practical applications. The mass spectra of dialkoxy- triazines [i] and trialkoxytriazines [2] have been studied rather thoroughly, while no in- formation is available on the dissociative ionization of monoalkoxy-symm-triazines. A number of rearrangement processes upon thermolysis including quaternization of ring nitrogens [3] and transalkylation [4] have been reported specifically for monoalkoxy derivatives of symm- triazine containing the 2-chloroethoxy fragment. The thermolysis of 2-chloroethoxy-symm- triazines permits the synthesis of a number of new polycyclic heterocyclic compounds [4, 5].

NS~ 2CH2X

I-Y

I X--H;II X=CN; III X=N3;IVX=CI; VX=ONO~

In the present work, we studied the dissociative ionization of 2-X-ethoxy-4,6-dichloro- symm-triazines (I-V) and compared the decomposition of these compounds with that for di- and trialkoxy derivatives. In addition, the mass spectral data may subsequently be used for identification of such compounds in complex mixtures of herbicides and their metabolites.

Despite the absence of molecular ions in individual cases in the mass spectra of the symm-triazines IV and V studied, a detailed analysis of the mass spectra using DADI and metastable defocusing methods and high resolution methods indicated general patterns for the decomposition of this class of compounds by the action of electron impact and a general scheme for the fragmentation:

*Deceased.

Lensovet Leningrad Technological Institute, Leningrad 198013. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1680-1683, December, 1983. Original article submitted March I0, 1982; revision submitted March 30, 1983.

1330 0009-3122/83/1912-1330507.50 �9 1984 Plenum Publishing Corporation

TABLE i. Mass Spectra of 2-X-Ethoxy-4,6-dichloro-symm-tri- azines*

I Com- I m / z value (relative intensity in % of maximum peak) pound I

I

II

III

ivt

v~

193 M~ (100), I67 (76), 150 (22), 131 (55), 124 (5), 111 (38), 95 (21), 89 (34), 88 (72), 69 (18), 63 (98) 218M~ (4), 166 (12), t49 (42), 130 (33), 110 (11), 94 (7), 91 (28), 88 (19), 87 (31), 63 (36) 234 M. +(0,2), 192 (2), 178 (13), I66 (26), 149 (34), I30 (3), 110 (41), 94 (8), 88 (37), 87 (100), 69 (33) 192 (5), 179 (61), 166 (75), 157 (54), 149 (100), 130 (8), I10 (6), 94 (23), 88 (23), 87 (94) 208 (7), 192 (11), 178 (61), 166 (23), 149 (33), 130 (8), l i0 (82), 94 ( l l ) , 88 (26), 87 (i00)

*The molecular ion and the ten strongest ion fragment peaks are given.

+The N + peak was not recorded.

OH 0CH2CH2X I +

~e' 130 M +

I - 0HCN ~ -X

N O+ II II+ ~..

/ N Cl N N -CI"

_ClCNH,I * ~ ' 8 7 ~ ...... CI ~s LN ~ CI -- " "

N ~ N H ~ 102

Cl ~ Cl - - ~

#P2' 139 ~ - ~ ] N ~+" el

~8' 88

- - - ~ C2H2NCI $

~ . l lO

0

~ . 157

OH

~3 ' 1 6 6 '

Here and subsequently in the text and tables, the number characterizing an ion gives the mass to charge (m/z) ratio; the m/z values for the chlorine-containing ions are given relative to the CI-35 isotope.

The high intensity of the molecular ion peak in the case of 2-ethoxy-4,6-dichloro-symm- triazine (I) is related to the electron-donor effect of the ethyl group. The peaks of most of the ion fragments in the mass spectrum of I (common for all the compounds) are shifted by a unit toward higher m/z values (Tables 1-3).

The formation of [M-- X] ~ ions (~l~ 192) is common for the decomposition of II-V. We should note that in the case of chloroethoxy derivative IV, elimination of a chlorine atom is found, and not loss of HCI which is characteristic for most chlorine-containing aliphatic compounds [6].

TABLE 2.

Com- pound

I II

III IV V

Intensity of Characteristic Ion Peaks (% X50)

M*

17,0 1,0 0,4

HL

o5 0,3 1,9 2,0

H2

33 95 58

170 59

Ha

11,3 2,8 5,1

13,0 4,1

H~

05

Cs+Hs

1 1 7 93

178 181 168

HB

61 57 04 11 11

H7

56 25 71 104 145

1331

a 193

, . t 124

!192 b

157~ ~149 i /o61 I I II

Fig. i. DADI spectra: a) ion 193 (M ~) for I and b) ion 192 (o~) for IV.

TABLE 3. Elemental Composition of Ions Observed in the Mass Spectra of 2-Ethoxy-4,6-dichloro-symm-triazine (I) and 2-(2-Chloroethoxy)-4,6-dichloro-symm-triazine (IV)

Com- pound

IV

Value

193 167 137 192 166 157. 149

Probable path of ion formation

[M-C2H2] + [M- C2HaCl] + [M-CI]+ (O 0 [Ol-C2Hd + (Oa) [O,-Cl]+ (04) [Ot-C2H2OH] + (02)

Elemental com- position of ion

CsHsC12ON3 CaHaCI2ONa CaH2C1ONa CsH4CI2ONa CaH2C12ONa CsH4CION3 CaHCI2Na

Exact mass

found calculated

192,9810 192,8888 166,9654 166,9676 130,9887 130,9920 191,9732 191,9720 165,9576 165,9575 157,0043 157,0002 148,9549 148,9576

The formation of the characteristic ion (Os, 166, Tables i and 2) may occur both from the molecular ion as a result of elimination of the C2H2X fragment or from the r ion as a restilt of the loss of aC2H= molecule. The DADIspectra of IV indicate that the~3 ions are formed as aresult of the process OI--C2H2,-+Oa . A study of the O2 ion (from compound IV) by the metastable de- focusing method showed that this is the only path for its formation. The analogous process for the decomposition of M + of I leads to the ion with m/z 167.

The DADI method was also used to establish that, along with the elimination of acetylene from the O1 ion, two additional processes occur: the elimination of a chlorine atom and C2H30 radical with the formation of the 04 and O2 ions, respectively (Fig. i, Tables 2 and 3).

The formation of Os ions (130, scheme) is possible by three pathways: i) directly from the molecular ion, 2) from the O1 ion, and 3) from the Oa ion. However, the latter two pathways were not supported by the DADI spectra. On the other hand, the DADI spectrum of the molecular ion of I indicated its relationship to ion 131. Thus, the O~ ion is formed directly from the molecular ion (scheme). The DADI spectrum indicates that the Or ion may be obtained either from the molecular ion or from the Oz ion. In our opinion, the latter process is preferred.

As noted above, the mass numbers of the fragments ions in the spectrum of I differ by a unit (hydrogen atom) from the mass numbers of the corresponding ions in the spectra of II-V. Comparison of the spectra of I and II-V indicates that there is a hydride shift to the heteroatoms in the molecular ions prior to fragmentation and migration occurs to all three nitrogen atoms and the oxygen atom in I. The O2 and O6 ions lose CICN, CICNH, and HOCN fragments (scheme) with the formation of the characteristic fragment ions O5 and 08.

On the whole, the dissociative ionization of monoalkoxy-symm-triazines differs from the fragmentation of di- and trialkoxy-symm-triazines by extensive destruction of the heterocycle, which is accompanied by the elimination of the CICN, CICNH, and HOCN fragments from the triazine ring.

1332

EXPERIMENTAL

The low-resolution and high-resolution mass spectra of I-V were taken on an MKh-1320 mass spectrometer with direct sample inlet. The ionizing electron energy was 70 eV. The resolution was 9000-10,000. The ion source temperature was 20-25~ The DADI spectra and metastable defocusing spectra were taken on a Varian MAT-311 mass spectrometer at 70 eV. The compounds studied were synthesized according to our previous procedure [7]. The purity and individuality of the compound samples were monitored by gas--liquid chromatography and liquid chromatography.

LITERATURE CITED

i. R.L. Ushakov, A. I. Makaya, V. G. Zaikin, V. I. Kelarev, P. A~ Kudryshov, A. F. Lunin, and N. A. Sokova, Zh. Obshch. Khim., 51, 1193 (1981).

2. J.A. Zeman and R. Worle, Org. Mass Spectrom., ~, 43 (1978). 3. V.V. Dovlatyan, K. A. Eliazyan, and L. G. Agadzhanyan, Khim. Geterotiskl. Soedin., No.

2, 262 (1977). 4. V.V. Dovlatyan, K. A. Eliazyan, S. M. Saakyan, and R. G. Mirzoyan, Khim. Geterotsikl.

Soedin., No. 9, 1275 (1981). 5. V.V. Dovlatyan, V. A. Pivazyan, K. A. Eliazyan, R. G. Mirzoyan, and S. M. Saakyan,

Khim. Geterotsik!. Soedin., No. 8, 1122 (1981). 6. A.A. Polyakova and R. A. Khmel'nitskii, Mass Spectrometry in Organic Chemistry [in

Russian], Izd. Khimiya, Moscow (1972). 7. A.B. Koshokov, I. V. Tselinskii, and Yu. A. Arevkov, Zh. Org. Khim., 16, 1330 (1980).

CYCLIZATION OF N-ALKYLAZINIUM CATIONS WITH BINUCLEOPHILES.

8.* ANNELLATION OF THE IMIDAZOLE RING WITH PYRAZINES AND QUINOXALINES

V. N. Charushin, V. G. Baklykov, O. N. Chupakhin, N. N. Vereshchagina, L. M. Naumova, and N. N. Sorokin

UDC 547.861.3'863'781.3'783.9.07:543.422.25.6

Monosubstituted and N,N'-disubstituted thioureas enter into cyclization with pyrazinium and quinoxalinium ion to form imidazo[4,5-b]-annellated pyrazines and quinoxalines.

Heteroaromatic cations containing a pyrazine fragment are capable of undergoing cycli- zation with various 1,3-bifunctional nucleophilic reagents (enamines [2], B-diketones [3, 4], amides of ~-keto acids [i], g-substituted acetimidic esters [5]). These reactions make it possible to obtain condensed heterocyclic systems based on the tetrahydroquinoxaline ring with annellated furan [3, 4] and pyrrole [I, 5] rings or a carbocyclic fragment [2]. In the present work we are reporting on the annellation of the imidazole ring to pyrazines and quinoxalines.

As a rule derivatives of imidazo[4,5-b]pyrazine and imidazo[4,5-b]quinoxaline are ob- tained by cyclizations of 2,3-diaminopyrazines (or quin0xalines ) [6-8]. We have established that derivatives of imidazo[4,5-b]pyrazine and imidazo[4,5-b]quinoxaline are formed in the reactions of 2,3-dimethoxycarbonyl-N-ethylpyrazinium fluoroborate (Ia) and N-alkylquinoxalin- ium iodides (Ib, c) with monosubstituted and N,N'-disubstituted thioureas (IIb-f) (Scheme, Table i).

*For Communication 7, see [i].

S" M. Kirov Ural Polytechnic Institute, Sverdlovsk 620002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1684-1688, December, 1983. Original article submitted March 23, 1983.

0009-3122/83/1912-1333507.50 �9 1984 Plenum Publishing Corporation 1333