814 MORGAN: ACTION OF FORMALDEHYDE ON

LXX1V.-Action of Formaldehyde on Amines of the Naphthalene Series. Payt 11.

By GILBERT THOMAS MORGAN, 1D.Sc.

IN a former paper on this subject (Trans., 1898,73, 536), an account was given of the interactions occurring, under various conditions, between formaldehyde and P-naphthylamine. The results showed that the chemical changes involved are somewhat complex, and differ considerably from those produced when this aldehyde is condensed with benzenoid amines.

I n order to obtain further evidence as to the nature of these reactions, a series of comparative experiments has been made with derivatives of P-naphthylamine, the object being so to regulate the action of the aldehyde that products could be isolated corresponding with each of the phases in the condensations of this reagent with the parent base.

When /?-naphthylamine is condensed with formaldehyde in cold alcoholic or acetic acid solution, 2 : 2'-dimethylenediamino-1 : 1'-dinaph- thplmethane is produced, 3 mols. of the aldehyde combining with 2 mols. of the base and 3 mols. of water being eliminated (Zoc. cit., 550). The substance isolated is in all probability the final product of

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 815

a succession of molecular rearrangements, for compounds of the simpler type CH,(NHR), have been obtained with the halogen deriva- tives of P-naphthylamine. 2 : 2’-Dimethylenediamino-l : 1’-dinaphthyl- methane, when heated with concentrated hydriodic acid and red phos- phorus, yields naphthacridine, and this result not only shows that the diamine contains one methylene group attached to two aromatic nuclei, but also that the positions of attachment of the linking carbon atom are the same in both compounds,

Although the orientation of the meso-carbon atom present in these bases has not been established either by direct synthesis or by refer- ence to some naphthalene derivative of known constitution, yet the fact, that, in the formation of homonucleol derivatives of /I-naph- thylamine, substitution invariably occurs in the contiguous a-, and not in the second P-position, is a strong argument in favour of the consti- tution generally assigned to napht hacridine.

Further confirmatory evidence has been obtained by a study of the behaviour of 1-bromo-2-naphthylamine and its chlorine analogue towards formaldehyde. These bases, when treated with this reagent in cold glacial acetic acid, yield methylene derivatives containing the radicle solely attached to nitrogen, methylernedi-1 -bromo-2-rcapht?ujl- amine, CH,( NH*C,,H,Br),, being obtained from 1 -bromo-2-nap h thyl- amine and methylene di-l-chZoro-2-nccpht?~ylnmine, CH2(NH*C,,H,C1),, from the corresponding chloro-compound. I n a preliminary note on the action of formaldehyde on substituted P-naphthylarnines (Proc., 1899, 15, lo), these substances were described as having the consti- tutional formulae, CH,:N*C,,,HeBr and CH,:N*C,,H,CI. A more detailed examination, however, has shown that each contains a methyl- ene group attached to two nitrogen atoms.

Anhydro-bases of the type RCH :NX are unsaturated compounds, and combine additively with hydrogen cyanide (von Miller and Plochl, Ber., 1896,29,1729; Eibner, AnnaZen, 1898,302,313), whereas the above compounds are not affected by this reagent, When boiled with dilute mineral acids, these methylene bases are hydrolysed into their gene- rators, a certain amount of resinous bye-product being simultaneously formed in the case of the bromo-compound. The methylene group may, however, be quantitatively eliminated by a modification of the method employed by Clowes and Tollens in the estirdation of this radicle in the methylene derivatives of the sugar series (Ber., 1899, 32, 2841). When warmed at 70° with excess of phloroglucinol dis- solved in glacial acetic acid, the anhydro-base decomposes in accord- ance with the following equation :

On diluting the solution with water, the insoluble phloroglucide,

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816 MORGAN: ACTION OF FORMALDEHYDE ON

(C7H60&, is completely precipitated, whilst the regenerated amine remains dissolved, and is easily identified in the filtrate.

These anhydro-bases are the first compounds of the type CH,(NHR), in the naphthalene series. Methylenedi-1-chloro-2-naphthylamine is quite stable in warm glacial acetic acid, and is not transformed into a dinsphthylmethane base when heated with 1 -chloro-2-naphthylamine and its hydrochloride.

Methylenedi-1-bromo-2-naphthylamine resembles its chlorine analogue, but is far less stable. It gradually decomposes, yielding a red, resinous substance when heated to 90° either alone or in solution.

These results indicate that the migration of methylene into the naphthalene nucleus is prevented by the presence of substitueut rad- icles in the a-position contiguous to the amino-group, and confirm the assumption made with reference to the position of the meso-carbon atom of naphthacridine and 2 : 2'-dimet.hylenediamino-l : 1'-dinaphthyl- methane.

The latter base contains, in addition, two other methylene radicles attached to the nitrogen atoms, and although the formula,

suggested for this substance in the former communication indicates its mode of formation, and also expresses its tertiary character, yet, in view of the fact that the nitrogen atoms are in the ortho-position relatively to the third methylene group, and there€ore in close prox- imity to each other, it is quite conceivable that a rearrangement of the valencies may occur, giving rise to a molecular structure repre- sented by one or other of the following formixlzle :

It might reasonably be supposed that a base containing two N:CH, groups, as indicated by formula I, would be hydrolysed by dilute mineral acids, and reduced by sodium and amyl alcohol; it should also combine additively with hydrogen cyanide. The base, however, is not affected by these reagents, and its stability is a point in favour of the view that rearrangement has taken place.

The substance indicated by formula I1 should also undergo hydrolysis, since the methylene groups are each attached to two nitrogen atoms, and, moreover, if any tendency exists for the linking up of the nitro- gen atoms by methylene, in the manner suggested by formula 11, it should be possible to obtain a compound of the type

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 817

by the action of formaldehyde on a monoalkyl derivative of P-naph- thylamine. When ethyl-/I-naphthylamine is treated in this way, 1 mol. only of formaldehyde interacts with 2 mols. of the amine, the product being a secondary base formed according to the equation

2 : 2'-Diethyldiamino-1 : 1'-dinaphthylmethane.

No further addition of methylene occurs, even when excess of the aldehyde is employed. As the linking up of the nitrogen atoms by methylene does not occur in t.his case, it is improbable tha t the con- densation product from P-naphthylamine has a constitution correspond- ing with 11.

The formula I11 gives a satisfactory explanation of the behaviour of the substance towards hydrolytic and reducing agents. Wi th regard to the action of hydriodic acid and red phosphorus, it will be noticed tha t the nitrogen atoms now form part of a seven-membered closed chain, and the production of naphthacridine may be expressed as a dis- ruption of this unstable system, giving rise to the stable six-membered ring of the acridine type.

Formaldehyde condenses with tertiary P-naphthylamine derivatives in accordance with the equation

This reaction was found to occur in the case of dimethyl-P-naphthyl- amine, diethyl-,haphthylamine, and dibenzyl-P-naphthylamine. I n each case, condensation was effected in glacial acetic acid, and i t was noticed that the heat developed by the reaction diminishes as the hydrogen atoms of the amino-group of the parent base are successively replaced by alkyl radiales. The reaction with P-naphthylamine is extremely vigorous, and the mixture must be cooled in a freezing mixture to prevent the formatim of tarry products; in the case of ethyl-P-naphthylamine , there is an appreciable rise of temperature, but the action is so far under control that no external cooling is needed, the condensation with diethyl-/3-naphthylamine proceeds very slowly at the ordinary temperature, and it is therefore advisable either t o apply heat or to add a dehydrating agent such as acetic anhydride.

The diphenylmethane bases containing the amino-group in the para- position, relatively to the methane carbon atom, are readily oxidised into colouring matters, whereas the dinaphthylmethane compounds, produced from P-naphthylamine and its nlkyl derivatives, do not yield coloured substances when submitted to this treatment.

VOL. LXXVII. 3 L

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818 MORGAN: ACTION OF FORMALDEHYDE ON

Dimethyl-a-naphthylamine was also condensed witjh formaldehyde in order to see whether a change in the orientation of the aminic nitrogen would affect this result; the product was a dinaphthyl- methane base, CH,(CloHG*~Me,),, which, like its P-isomeride, gave no colour reaction with lead peroxide. Friedlander and Welmans prepared the corresponding phenyldinaphthylmethane base from di- methyl-a-naphthylamine and benzaldehyde, and obtained a similar negative result with this oxidising agent (Be?.., 1888, 21, 3123).

Since the methylene and benzylidene groups invariably enter the ring in accordance with the “ para-ortho ” law, it follows tha t the condensation products from dimethyl-a-naphthylamine rday have one of three constitutions ; they may be either aa-(dipara), ap-(paraortho), or @@-( diort ho)-dinaphth ylmet hane derivatives. The non-f ormation of a coloured oxidation product seems to indicate tha t the bases are @/%compounds, containing both aminic nitrogen atoms in the ortho- position relatively to the methane carbon atom, but, although this fact would be conclusive evidence in the benzene series, yet it cnn- not be accepted as final in the case of these naphthalenoid deriva- tives, inasmuch as colouring matters of the rosaniline type containing only naphthalene nuclei have never been obtained, and it is there- fore probable tha t the nature of the aromatic residue attached to the central carbon atom plays an important part in modifying the behaviour of the compound towards oxidising agents.

Naphthacridine is produced from b-naphthylamine and formalde- hyde when the condensation takes place in the presence OF mineral acids, a labile isomeride, isonaphthacridine, being formed as an intcr- mediate product.

The production of an acridine base in one operation-a change involving simultaneous oxidation and the elimination of ammonia- is peculiar to P-naphthylamine; in the benzene series, the inter- mediate products can usually be isolated, owing to their greater stability. m-Toluylenediamine, for example, when condensed with formaldehyde, yields a tetraminodiphenylmethane containing two amino-groups in the ortho-position relatively to methylene ; this base is quite stable, and only loses ammonia on digesting with acids, the product being the leuco-base of acridine yellow, which furriishes the colouring matter by subsequent oxidation (Leonhardt, D. R.-P, 52324, 70935).

The formation of naphthacridine may be represented as taking place in the following stages :

(1) 2Cl0H,*NH, + H,CO = Cl,H,<NH~CloHG C H + NH, + H,O, the

di hydronaphthacridine (unstable) at once becoming oxidised. (’) C10H6<i2>C10HG + = CIOH,<_NH>CIOHG CH(0H)

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AMINES O F THE NAPHTHALENE SERIES. PART I i , 819

and the intermediate oxidation product undergoing further conden- sation.

When ethyl-P-naphthylamine is substituted for P-naphthylamine in this reaction, 2 mols. of the base condense with 1 of the aldehyde, and ethylamine is eliminated instead of ammonia. The product con- tains oxygen, and has the composition C,,H,,ON. The analytical data point to its being an ethyl derivative of the intermediate oxida- tion product of dihydronaphth:icridine, and this view of its constitution is in accordance with the mode of formation

zC,,H7NHEt + H,CO + 0 = C,,HG<~~~~&CloH, + EtNH, + H,O.

ur-Tetrabydrodiethyl-P-naphthylamine, which, according to Bam- berger’s researches, must be regarded as a benzenoid amine, does not react with formaldehyde under the conditions employed in the forma- ation of 2 : 2’-tetrethyldiamino-1 : l’-dinaphthylmethane. The methyl- ene group shows very little tendency to take up the ortho-position relatively to an amino-radicle in the nucleus of a benzenoid amine, only a very small yield of the clitolylmethane base, CH,(C,H,Me*NH,), [Me : CH, : NH, = 1 : 3 : 41, being obtained by the intramolecular rearrangement of methylenodiy-toluidine (Eberhardt and Welter, Bey. , 1894, 2’7, 1804). The reactivity of the hydrogen atom in the contigiious a-position is a property of P-naphthylamine, and disappears when the naphthalenoid character of the aromatic nucleus is destroyed.

EXPE R I M E NT AL.

Preparation of l-Brorno-2-).~up~th~lumine.

Lellmann and Schmidt brominated aceto-P-naphthalide dissolved in 50 per cent. acetic acid (Bey . , 1887, 20, 2154), buc the recrystallised acetyl compound is so insoluble in this medium that it was found more convenient to dissolve it in glacial acetic acid.

The following method was found to give a good yield of l-bromo- 2-acetonaphthalide. Aceto-P-naphthalide (30 grams) was dissolved in 7 parts of glacial acetic acid, and the theoretical quantity of bromine (26 grams) dissolved in 2 parts of the same solvent slowly added. The mixture was agitated continuously, and after the addi- tion of the bromine, the precipitate of 1-bromo-2-acetonaphthalide was collected, washed with glacial acetic acid, dissolved in alcohol, and hydrolysed by boiling with concentrated hydrochloric acid until the

3 ~ 2

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820 MORGAN : ACTION OF FORMALDEHYDE ON

precipitation of 1-bromo-2-naphthylamine hydrochloride was complete. The base, obtained by decomposing the hydrochloride with caustic soda, was repeatedly crystallised from light petroleum, and separated in colourless needles melting a t 63".

Action of Forma Zdehyde on 1 -Bromo- 2-naphthyZc~mine. Methylenedi- 1 - bromo-2 -napiith y lamine.

1-Bromo-2-naphthylamine dissolved in four times its weight of glacial acefic acid was treated with excess of formaldehyde solution. There was no apparent change, and no rise of temperature was observed, but on diluting the solution with water, a white precipitate was obtained which melted above 100". The substance, which was produced with equal readiness by the addition of formaldehyde solu- tion to an alcoholic solution of 1 -bromo-2-naphthylamine, was recrys- tallised from alcohol, when the melting point rose to 141-343". It was soon noticed that the new compound was somewhat unstable in character, for its solution in alcohol, benzene, or chloroform darkened on boiling, and a red, resinous substance was precipitated. Great care had to be exercised in order to obtain a colourless specimen. A portion of the substance, dried on porous plates, was finely powdered and added to benzene heated nearly to boiling ; the substance rapidly dissolved, and the solution was filtered into a vessel provided with a tightly fitting stopper, and allowed to cool. The compound crystallised in colourless needles with a silky lustre, and melted a t 1 4 5 O .

0.2011 gave 0,4118 CO, and 0-0674 H20. 0*1200 ,, 0.2432 CO, ,, 0.0438 H,O. C=55*27; H=4.05. 0,1878 ,, 0.1530 AgBr. Br = 34.67. 0.1453 ,, 8.1 C.C. moist nitrogen at 22" and 765 mm. N = 6.35.

C,,H,,N,Br,requiresC= 55-26; H = 3-51; Br= 35*08;.N=6*14percent.

When heated for a short time a t go", the colourless, silky needles become reddened, and the same chnnge takes place more slowly when the crystals are exposed to light.

MethyZencdi-l-bromo-2-naphthylamine, CH,(N H* Cl,,H6Br)2, when warmed with dilute acids, is partly hydrolysed into its generators, form- aldehyde and 1-bromo-2-naphthylamine ; at the same time, a portion is decomposed, yielding the resinous product previously mentioned.

A weighed quantity of the anhydro-base (0.4-0.7 gram) was sus- pended in 12 C.C. of a glacial acetic acid solution of phloroglucinol, and heated a t 70" for about 2 hours, the solution was then diluted with an equal bulk of water and the precipitated phloroglucide col- lected in a Gooch crucible, dried at 110-120°, and weighed.

C=55-84; H = 3.72.

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 821

004428 gave 0.1033 phloroglucide. CH, = 2.35. 0,7273 ,, 0.2369 9 9 CH, = 3.25.

CH,(CloH,Br), requires CH, = 2.82 per cent.

The regenerated 1-bromo-2-naphthylamine was obtained by render- ing the filtrates ammoniacal ; after crystallisation from light petroleum i t melted at 60° (corr. 63")

Preparation of l-CI~Zo1'0-2-nuphtl~yICCmine.

Cleve states tha t 1-chloro- 2-acetonaphthalide is produced by pass- ing one molecular proportion of chlorine into a solution of aceto-p- naphthalide in dilute acetic acid. Recrystnllised aceto-P-naphthalide is almost insoluble in dilute acetic acid, and it was found impossible to obtain a clean product, by using this method. Chlorination by means of sulphuryl chloride did not lead to very satisfactory results.

I am indebted to Dr. Wynne for the details of the following method. A solution of 110 grams of aceto-P-naphthalide in 1800 grams of glacial acetic acid was heated a t 45-50', and chlorine was passed in until the increase in weight corresponded with the addition of one molecular proportion of the gas. The l-chloro-2-acetonaphthalide, which separated during the action, was collected, recrystallised from alcohol, and hydrolysed by boiling with excess of hydrochloric acid in alcoholic solution. The hydrochloride of 1 -chloro-2-naphthyl- amine, precipitated on cooling the alcoholic solution, was decomposed with caustic soda ; the base, after repeated crystallisation from light petroleum, separated in colourless needles melting a t 60".

Action, of Formaldehyde on 1 -ChZoro-Z-nup~~thyZirni~. Methylenedi-l- chZo~o-2-naphthyZamine.

Methylenedi-l-chZoro-2-~phtlhyIccmilze, CH,(NH*C,,H,Cl), was pre- pared in a precisely similar manner to the bromo-derivative just described, by the action of formaldehyde on 1-chloro-2-naphthylamine in alcoholic or glacial acetic acid solution. The compound crystallises from chloroform or benzene in colourless needles with a silky lustre. It melts a t 179-180O. A specimen, crystallised from chloroform, was analysed with the following results :

0,1907 gave 0.4816 CO, and 0.0821 H,O.

0.1502 ,, 10.3 C.C. moist nitrogen at 15O and 768 mm. Nz7.98 .

With another specimen, crystallised from benzene, the following

C = 68.87 ; H = 4.78. 0.1447 ,, 0.1153 AgC1. C1=19.71.

numbers were obtained :

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822 MORGAN: ACTION OF FORMALDEHYDE ON

0.1520 gave 0.3831 CO, and 0.0681 H,O. C = 68.60 ; H = 4.98. 0.1514 ,, 0.1194 AgC'I. Cl=19-50.

C,,H,,N,Cl,requiresC = 68.66; H = 4.37; C1= 19.34; N = 7.63 percent.

I n outward appearance, this compound closely resembles the bromo- derivative, but it is *far more stable, and its solution in benzene or chloroform may be boiled for several hours without decomposition. When heated with dilute mineral acids, it is completely hydrolysed into its generators, formaldehyde and 1-chloro-2-naphthylamine.

The decomposition with phloroglucinol was carried out in precisely the same manner as in the case of the analogous bromine compound.

0.4806 gave 0.1687 phloroglucide. CH, = 3.51. 0.6210 ,, 0.2140 9 , CH, = 3.44.

CH,(NH*CloH,Cl), requires CH, = 3-81 per cent.

The regenerated 1-chloro-2-naphthylamine was precipitated from the filtrates and recrystallised from petroleum; it then melted at 59' (corr. 60').

Preparation of D i m e t ~ y L P - n a p ~ ~ t ~ y l a ~ ~ n e .

This base is most conveniently obtained by the method employed by Bamberger (Bey., 1889, 22, 1306). 143 grams of P-naphthylamine (1 mol.), intimately mixed with caustic soda (2& mols.) and 90 C.C. of water, are heated with methyl iodide (3 mols.) at 130' for 5-6 hours. The P-naphthyltrimethylammonium iodide thus produced is separated from the admixed oily impurities by crystallisation from water. It separates in lustrous, white leaflets, the yield obtained from the above quantities being about 210 grams.

A small amount of dimethyl-P-naphthylamine is produced by the dry distillation of the quaternary iodide, but the base is obtained in almost quantitative yield by gently heating the corresponding chloride or hydroxide.

The chloride is produced by digesting a warm solution of the iodide with freshly precipitated silver chloride ; it is extremely soluble, and can only be isolated in the form of its platinichloride. This substance crystallises from alcohol in transparent, orange plates, and melts a t 198'.

0.2225 gave 0.559 Pt. (CloH7NMe,),PtCl, requires Pt = 25.00 per cent.

When the aqueous solution of /3-naphthyltrimethylammonium chloride is evaporated to dryness, methyl chloride is evolved and dimethyl-P-naphthylamine remains in the residue. The same result is attained by evaporating down a solution of P-naphthyltrimethyl- ammonium hydroxide prepared by digesting the iodide with moist

Pt = 25-12.

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 823

silver oxide, I n both cases, the reaction is completed by raising the temperature of the residue to 130'. The dimethyl-P-naphthylamine solidifies on cooling, and, after two crystallisations from dilute methyl alcohol, melts at 46'.

Action of Formaldehyde on Dimethyl-P-naphthylamine. met h y Id iamino - 1 : l'-dinap?bthp Zme thane.

Dimsthyl-P-naphthylamine (10 grams), dissolved in 50 grams of glacial acetic acid and 20 grains of acetic anhydride, is treated with 5 grams of formaldehjde solution (35 per cent,). There is no change in the colour of the solution, nor is there any appreciable rise of temperature, the reaction being far less energetic than in the case of P-naphthylamine. After remaining for 12 hours, the solution is poured into cold water, the excess of acid neutralised with ammonia, and the precipitated base dried on porous plates. The yield is quantitative.

2 : 2'-TetramethyZdiamino-l: 1 I-din~phtl~yEmeth~ne, CH,[C,,H,*N( CH,), I,, is readily soluble in methyl or ethyl alcohol or ethyl acetate, and crystallises from these solvents in transparent, colourless, flattened prisms with obliquely truncated ends.

2 : 2'-Tetra-

It melts a t 144".

0.1317 gave 0.4095 CO, and 0-0878 H,O. 0.1529 ,, 0.4719 CO, ,, 0.1042 H,O. C = 84.71 ; H = 7.57. 0.1041 ,, 7.4 C.C. moist nitrogen a t 21' and 756 mm. N = 8.04.

The picrate crystallises from alcohol in yellow leaflets melting at 193-1 94'.

Unlike dimethy1-P. naphthylamine, the new base shows no tendency to form a quaternary iodide ; combination does not occur when it is heated for some hours at 110' with excess of methyl iodide.

C = 84.80 ; H = 7-40,

C,,H,6N2 requires C = 84.74. H = 7.34 ; N = 7.91 per cent.

Pwparation of Diethyl-P-naphthylamine.

Diethyl-P-naphthylamine has been studied previously (Beis., 1889, 22, 1761), but no account of its preparation is to be found in the literature. It may, however, he prepared more readily than dimethyl- P-naphthylamine, its lower homologue, as the ethylation stops at the formation of the tertiary base.

A n intimate mixture> of 39 grams of P-naphthylamine, 22 grams of caustic soda, and 22 C.C. of water was heated with 85 grams of ethyl iodide (2 mols.) in sealed tubes, at 120°, for 7-8 hours. The product was an oil, which was dried over caustic potash, and subsequently fractionated. The greater portion distiiled over between 309' and 313'. This fraction did not give a nitrosamine when treated with hydrochloric acid and sodium nitrite, and was not acted on by acetic

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824 MORGAN ACTION OF FORMALDEHYDE ON

anhydride. It was again fractionated, and the portion boiling at 310-312' (uncorr.) under 764 mm. pressure was utilised in the f 01 lowing experiment.

Action of Foymddehyde on o.;etJ~yZ-P-napht~~yZa~in~. 2 : 2'-TetyaethyL

A solution containing 18 grams of diethyl-/3-naphthylamine in 30 grams of glacial acetic acid and 8 grams of acetic anhydride was treated with 5 grams of formaldehyde solution (35 per cent.); the mixture, after remaining for 12 hours, was heated to boiling for a few minutes, and then added to a large volume of cold water. The solution mas neutrnlised with ammonia, and the semi-solid mass which separated was collected and drained on porous plates. The yield of crude base was about 16 grams.

diamino-1 : 1 '-dinaphtl$Zmethane.

2 : 2'- Te traet h y ldiarnino- 1 : 1 '-d inaphth y h e thane, CH2 P I OH,N(C,%) 21 2 9

crystallises from ethyl acetate in large, transparent, colourless, tabular prisms, melts at 114O, and is more soluble than its tetramethyl homo- logue, which it resembles in appearance. For the purpose of analysis, a portion was crystallised from ethyl alcohol.

0.1436 gave 0-4500 CO, and 0.1083 H,O. C = 85.46 ; H = 8.38.

0.1845 ,, 11 C.C. moist nitrogen at 17" and 764 mm. N = 6 94. 0.3554 ,, 21.7 C.C. ,, ,, ,, 1 3 ~ 5 ~ and 741 mm. N = 7-06,

C29H34N2 requires C = 84.88 ; H = 8.29 ; N = 6.83 per cont.

I was enabled, through the kindness of Dr. Sidney Williamson, to compare the diethyl-P-naphthylamine, prepared by the above method, with a specimen of the base employed in his researches with Bamberger (Bey., 1889, 22, 1761). The latter specimen, when con- densed with formaldehyde, yielded a base which crystallised from ethyl acetate in transparent, tabular prisms melting at 114O, and was iden- tical in every respect with the base obtained from my preparation.

0.2118 ,, 0.6626 CO, ,, 0,1627 H,O. C=85*31 ; H=8*53.

Ebrrnaldehyde and ar-TetrarTLydrodiethyl-P-napht~~Za~~n~.

Six grams of ar-tetrahydrodiethyl-/3-naphthylamine (b. p. 296O), dissolved in 48 grams of a mixture of glacial acetic acid and acetic anhydride (1 : I), were treated at the ordinary temperature with 3-5 C.C. of formaldehyde solution (35 per cent.). After a fortnight the solution was neutralised with ammonia and extracted with ether ; the basic oil obtained proved to be the unaltered substance and 3-4 grams were recovered boiling at 293-297O under '748 mm. pressure,

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 825

A similar negative result was obtained on heating the solution of base and aldehyde a t 100-llOo for several hours.

Benzylation of P-Naphthpkamine. Dibenxyl-P-naphthpZc~~~ne.

A mixture of P-naphthylamine (1 mol.) and benzyl chloride (2a mols.) with a slight excess of 10 per cent. caustic soda solution, was heated a t 1OO'for 7-8 hours, and the tarry product, after washing with warm water until free from alkali, was digested with cold ethyl alcohol to remove any unaltered P-naphthylamine. When a small portion of the alcoholic washings treated with hydrochloric acid and sodium nitrite no longer gave a red coloration with an alkaline solution of P-naphthol, the residue was dissolved in hot ethyl acetate. The solu- tion, on cooling, deposited hard, nodular crystals melting at 1189 After repeated crystallisations from alcohol, in which the base is sparingly soluble, transparent, colourless lath-like crystals were ob- tained, melting a t 11 9-1 20' ; these became slightly pink on exposure to the air. On analysis :

0.1542 gave 0.5055 CO, and 0.0899 H,O. C =89*39 ; H = 6.42. 0.1074 ,, 4.3 C.C. moist nitrogen at 19' and '763 mm. N=4*62.

C,,H,,N requires C = 8!3*16 ; H = 6.50 ; N = 4.30 per cent.

Dibenxyl-P-naphthykcbmine, C,,H7*N(C,H7),, crystallises in the free state from glacial acetic acid, and its salts are decomposed by water.

The picrute crystallises from an alcoholic solution in opaque, yellow scales, melting at 137-1338'.

The pkatinichloride is obtained from an alcoholic solution as a brownish-yellow precipitate.

Monobenzyl-P-naphthylamine, which has been prepared by reducing benzylidene-B-naphthylamine with sodium amalgam in alcoholic solu- tion (Annulen, 1887,241, 260), was not obtained by direct benzylation.

Action of Formakdehyde on I)ibenxyLP-)zc~phthyZarnine. 2 : 2'-TetrabenxyZ- diamino-l : ll-dinaphthylrnet~inne.

The condensation with formaldehyde takes pIace less readily with dibenzyl-/I-naphthylamine than with the two dialkyl-P-naphthylamines.

A solution of 3.2 grams of dibenzyl-P-naphthylamine in 40 grams of glacial acetic acid and 3 grams of acetic anhydride was treated with 5 C.C. of formaldehyde solution (36 per cent.), the mixture heated to boil- ing and then allowed to cool. The first crop of crystals which separated consisted of the unaltered base, and melted at 114'. On allowing the filtrate to remain overnight, a second crop separated ; this appeared to be a mixture, for it melted somewhat indefinitely, softening a t 140° and fusing at 154'. After recrystallisation from ethyl acetate, the

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826 MORGAN: ACTION OF FORMALDEHYDE ON

melting point was raised to 164". As condensation had evidently been effected, the experiment was repeated with a similar mixture, but on boiling for 4-5 hours only tarry products were obtained.

The condensation product was best obtained in the following manner. A solution containing 6 grams of dibenzyl-P-naphthylamine in 60 C.C.

of glacial acetic acid and 4 grams of acetic anhydride was treated in the cold with 2.5 C.C. of formaldehyde solution, and then gently boiled for 30-45 minutes; on cooling, it deposited a white, crystalline sub- stance which melted at 159 -160". 2 : 2 -Tetrabenzyldiamino-l : l'-di- naphthyZmetAane, CH2[ Cl,,H6*N(C7H7)2]2, is sparingly soluble in alcohol, and forms transparent, colourless, glistening plates melting a t 164-165'.

0.1516 gave 0.4977 CO, and 0.0883 H,O. C,,H,,N, requires C = 89.36 ; H = 6.38 per cent.

The three dinaphthylmethane derivatives, unlike tetramethyl- diaminodiphenylmethane, do not yield coloured substances on treat- ment with lead peroxide or benzoyl chloride.

C=89-53 ; H- 6.40.

Action of Tormldehyde on Dimethyl-a-naphth~zamine. 1 ; 1'-Tetramethyl- diaminodina phthy Zme t ham.

Dimethyl-a-naphthylamine was prepared according to the method given by Hantzsch (Ber., 1880, 13,1348 ; 1888, 21, 3124) and purified from traces of a-naphthylamine and monomethyl base by treatment with acetic anhydride. The product employed in the following experi- ments boiled a t 270-271" under 755 mm. pressure.

A solution of 4 grams of dimethyl-a-naphthylamine in 20 grams of cold glacial acetic acid, treated with 1 C.C. of formaldehyde solution (35 per cent.) and 1 C.C. of concentrated hydrochloric acid, was allowed to remain overnight, then heated to boiling for a few minutes and poured into cold water. The excess of acid was neutralised with ammonia and the pasty mass which separated was drained on porous plates and recrystallised from ethyl acetate.

1 : l'-Y'etramethyZdiarninodinaphtAylmethane, CH,[C,,H,*N(CH,),],, separates from ethyl acetate in clusters of hard, transparent, colourless prisms which become tinged with yellow on exposure ; it melts at 177".

0.1798 gave 0.5554 CO, and 0.1164 H20. c! = 84.28 ; H = 7.19. 0.1499 ,, 0.4650 CO, ,, 0*1007 H20. C=84*60 ; H=7*47. 0.0865 ,, 5.8 c.c.moist nitrogenat 14.5Oand 768 mm. N = 7.95.

Since there is a possibility of obtaining three isomerides in this condensation, the mother liquors from the compound melting at 177"

C25H2GN2 requires C = 84-74. H = 7.34 ; N = 7.91 per cent.

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AMINES OF THE NAPHTHALENE SERIES. PART 11. 827

were allowed to evaporate nearly to dryness. I t was found, however, that the crystals which had separated melted at 172" and gave the same melting point when mixed with an equal amount of the substance from the first crop.

1 : 1'-Tetramethyldiaminodinaphthylmethane is not oxidised to a coloured substance by lead peroxide; in this respect it resembles the compound o5tained by Friedliinder and Welmans from dimethyl-a- naphthyhmine and benZaldehg.de (Be?*., 1888, 21, 31 23).

Ethyl-P-naphthylamine was prepared according to the method described by Otto Fischer (Rer., 1893, 26, 193), and the product employed in the following experiments, boiled at 309- 31 1' under 758 mm. pressure. The freshly distilled base is almost colourless, but rapidly darkens on exposure to light, and develops an intense blue fluorescence.

2 : 2'-DietlLyEdianaino-l : 1 '-dinap?~thylamine, CH,( C,,H,*NH* C,H5),. -To prepare this base, 7 grams of formaldehyde solution are added to a solution of 20 grams of ethyl-P-naphthylamine in 80 grams of glacial acetic acid. The solution assumes a deep colour, and rapidly becomes pasty from the separation of a crystalline precipitate ; the reaction is accompanied by an appreciable rise in temperature, but cooling with ice is not necessary. The precipitate is washed with acetic acid and alcohol until colourless ; the filtrate is added to a large volume of water, the acid neutralised with ammonia, and the yellow, viscid mass which separates extracted with chloroform; the extract yields a further quantity of the condensation product. The precipitate and the substance extracted with chloroform are mixed together, and crystallised from ethyl acetate, from which the base separates in well defined, transparent, colourless plates, melting at 197-1 98'. The following numbers were obtained on analysis :

0.1124 gave 00.3475 CO, anti 0.0761 H,O. 0.1450 ,, 0.4500 CO, ,, 0.0960 H,O. C = 84.64 ; H = 7.35. 0.1685 ,, 11.6 C.C. moist nitrogen at Z O O and 765 mm. N = 7-82.

The experiment was repeated with a large excess of formaldehyde in order to see whether further condensation in the side chains would occur, but 2 : 2'-diethyldiamino-1 : 1'-dinaphthylmethane was the only product. This base is also produced by dissolving ethyl-P-naphthyl- amine hydrochloride in glacial acetic acid, and adding successively the requisite quantities of sodium acetate and formaldehyde solution,

C = 84.31 ; H = 7.52.

Cz5H2sNz requires C = 84-74 ; H = 7-34 ; N = 7-91 per cent.

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828 MORGAN: ACTION OF FORMALDEHYDE ON

The dibenxoyl derivative, CH2[C,oH6*~(C,H,)*COoC6H,1,, was pre- pared by the Schotten-Baumann method. The semi-solid mass, obtained by shaking up the base with excesg of benzoyl chloride and a solution of caustic potash, was triturated with ether to remove an oily impurity, and the crystalline solid, after drying on porous plates, extracted with benzene. To the filtered solution, an equal volumo of petroleum was added, and the benzoyl derivative, obtained in small, colourless plates, was recrystallised from alcohol. It forms trans- parent, colourless, highly refractive prisms, and melts at 196". This melting point is very close to tha t of the original base, but a mixture of the two substances melts at 171-172O.

0,1650 gave 7.1 C.C. moist nitrogen at 18' and 764 mm. N = 4.99. C,,H,,O,N, requires N = 4.97 per cent.

Action of Formccldehyde on EthyGP-naphthylainine Hydrochloride in Alcoholia Solution.

Twenty-five grams of ethyl-P-naphthylamine hydrochloride dis- solved in 300 grams of alcohol were heated for 15 minutes with 13 grams of formaldehyde solution. The colour of the solution changed from light brown to deep red, and a precipitate was produced. The alcohol was removed as far as possible by distillation, the residue washed with water, filtered, boiled with alcoholic potash, poured into water, and the precipitated bases collected, dried on porous plates, and extracted with benzene. The benzene extract, on cooling, yielded a dark brown, crystalline precipitate, which was again crystallised from this solvent. The product was a mixture of two bases, and their com- plete separation was a matter of some difficulty. The mixture was dissolved in ethyl acetate, and the first crop of crystals repeatedly crystallised from this solvent until the melting point remained con- stant, The substance separated in colourless plates melting a t 197-1998", and was identified as 2 : 2 -diethyldiamino-1 : 1'-dinaphthyl- methane, the base obtained in the preceding condensation.

The ethyl acetate mother liquors, on the addition of alcohol, gave a light brown, crystalline precipitate, which was crystallised from alcohol until the melting point remained constant at 157-158O. The substance separates in transparent, colourless prisms, which become opaque on warming, and darken on exposure to light. A portion, dried a t 90-100" until constant in weight, was analysed, with the following results :

0,2547 gave 0.7915 CO, and 0.1441 H,O. C = 84-70 ; H = 6-37, 0.151 1 ,, 0.4703 CO, ,, 0.0882 H,O. C = 84.88 ; H = 6.40. 0.1710 ,, 6.3 C.C. moist nitrogen at 19Oand 770 mm. N = 4-29.

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AMINES OF THE NAPHTEALENE SERIES, PART If. 829

Another specimen, crystallised from benzene, remained constant in

0-1739 gave 0.5401 CO, and 0.1028 H,O. C = 84.70 ; H = 6.56. 0.1969 ,, 0.6085 GO, ,, 0.1147 H,O. C=84.28 ; H=6.47. 0.2558 ,, 9.6 C.C. moist nitrogen at 16' and 772 mm. N = 4.44.

C,,H,,ON requires C = 84.92 ; H = 5-84 ; N = 4.30 per cent.

The analytical results indicate that the substance contains oxygen, and that it is formed by the elimination of half the nitrogen from two mols. of ethyl-/3-naphthylamine (see p. 819).

It is very soluble in ethyl acetate or chloroform, and crystallises from its solution in either solvent in well defined, colourless prisms. When crystallised from alcohol and dried a t the ordinary temperature, it contains 1 mol. of alcohol of crystallisstion. An air-dried specimen gave the following numbers :

0.1403 gave 0.4154 CU, and 0.0910 H,O. C,,HI90N + C,H,O requires C = 80.86 ; H = 7.01 per cent.

The base, C,,H,,ON, when treated with acetic anhydride, benzoyl chloride (Schotten-Baumann method), or hydriodic acid and red phos- phorus at 170" gives rise to resinous products.

The formation of a compound having the above constitution in- volves the elimination of ethylamine, and this base was identified in the following manner. The aqueous filtrate from the original precipitate was rendered alkaline, and distilled in a flask fitted with Kjeldahl bulbs, the ammoniacal gas evolved being passed into hydrochloric acid. On the addition of platinic chloride, an orange platinichloride was obtained which crystallised in hexagonal plates.

weight when heated for lfr hours at 90-looo, and was analysed.

C = 80.74 ; H = 7-20.

On analysis :

0.3403 gave 0.1322 Pt. Pt = 38.84. 0.3926 ,, 0.1522 Pt. Pt=38.80.

(C2H,*NH,)2,H2PtCl, requires Pt = 39.00 per cent.

Considerable progress has been made in the study of the action of benzaldehyde and its analogues on the alkyl and halogen derivatives of /3-naphthylamine, and the results will be made known in a subse- quent communication.

ROYAL COLLEGE OF SCIENCE, LONDON, SOUTH KENSINGTON, s. w.

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