907 XCI. -Homonucleul Tri-derivatives of L\Tc~phtlzulen,e. By RAPHAEL ;\Im,DoLd, F.R.S., and FEEDERICK WILLIAM STREATFEILD, F.I.C. SIXCE the last communication on this subject (Trans., 1892, 765) the investiga,tion has been carried on during all available opportunities, and results have been obtained which appear t o us sufficiently in- teresting to warrant, our offering another instalment t o the Society. Dibromonitroizaphthalene, CloH,Br*NO,.Br = 1 : 2 : 4, rn. $7. 1 1 7 O . - A considerabje quantity of this compound, which was briefly de- scribed in the previous communication (p. 769), has been prepared and some of its derivatives studied. Analysis of a specimen purified by crystallisation from alcohol gave the following results. N = 0.1640 gave 5.95 c.c.moist nitrogen at 14-25' and 7.56-5 mm.0.1520 gave 0.1715 AgBr. C,,H5Br2NO2 requires Br = 48-33 ; N = 4-23 per cent. Dibromo-/3-naphthylamine, CInH,Br*NH2*Br = 1 : 2 : 4, m. p. 106-107°.-The reduction of the nitro-compound is best effected by means of zinc dust and acetic acid in alcoholic solution. The filtered liquid is largely diluted with water, when the dibromonaphthyl- amine separates out in the form of whitish needles, which must be collected as rapidly as possible and protected from the action of light, as when moist and impure they appear to be susceptible of photo- chemical oxidation, and become coloured on exposure to the air. The pure compound is, however, quite stable, and when dry consists of white, silky needles melting a t 106-107°, and very readily soluble in alcohol, benzene, and all the ordinary organic solvents.A specimen was purified for ar,alysis by crystallisation from dilute alcohol and benzene in succession. N = 4-64. 4.23. Br = 48.01. 0.1238 gave 5 C.C. moist nitrogen at 17" and 754.3 mm. (3.0835 gave 0.1040 AgBr. C,,H,Br2NH2 requires Br = 53.15 ; N = 4.63 per cent. The compound is devoid of basic properties. When boiled in glacial acetic acid with a little acetic anhydride, it readily acetylates. The acetyl derivative was purified by crystallisation from acetic acid and alcohol in succession, and was obtained in the form of white needles melting at 220-221". 0.1567 gave 5*6 C.C. moist nitrogen at 15.5Oand 761 mm. N = 4.1 7. VOL. LXBTI. 3 P Br = 53.0. CloH5Br2*NH-CrH,0 requires N = 4-08 per cent.908 MELDOLB AND STREATFEILD : Action of ATitmus acid 072 Dib1'0731o-P-11~lphthl~I~~11~ii~e.An attempt to replace the NH2-group in the above cornpound by hydroxyl by the " diazo reaction " led to an unexpected result. The details of the experiment are as follows. The substance is dissolved in glacial acetic acid, the solution filtered, if necessary, and strong sulphuric acid added till crystals of the sulphate begin to sepal-ate out. The calculated quantity (or n little excess) of sodium nitrite necessary to diazotise the dibromo- naphthylamine is then added in small portions in the solid condition to the well cooled solution, and the mixture allowed to remain for some hours with frequent stirring. On gradually diluting with water, a t the same time keeping the liquid cool, a clear solution is obtained, and there is no doubt that a t this stage a diazo-salt (sulphate) is present in the solution.On raising the latter to the boiling point, little or no nitrogen is evolved, aiid an ochreous substance gradually separates. The liquid when quite cold dcposits a further quantity of a substance crystallisiiig in hair-like ochreous needles. The product, on being collected and washed, proved to be non-phenolic and t o con- tain nitrogen, and was not, therefore, the dibromo-&naphthol which we were endeavouring to prepare. This fact, combined with the observation above recorded, that practically no nitrogen is evolved on boiling the solutioii of the diazo-sulphate with water, indicated that the ordinary diazo decomposition had not taken place.The product, on further examination, was found to be resolvable into two portions, one soluble in boiling water, from which i t crystallises on cooling in the form of yellowish, filamentous needles, which become brown on exposure to light. The portion insoluble in boiling water consisted of an ochreous compound, very insoluble in all mlvents, and most difficult to deal with. I t probably contains diazoarnido- or an amido- azo-compound, but we have not succeeded as yet in isolating any definite substance from it. The compound crystallising from water had a decomposing point OF about 148-151°, a t which temperature: i t froths up with almost' explosive suddenness. It is extremely soluble in alcohol, benzene, glacial acetic acid, and organic solvents generally.A specimen twice crystallised from boiling water was analysed with the follotying results, from which it appears that the substance is a diazoxide. N = 0.1058 gave 9.8 C.C. moist nitrogen a t 12" and 763.7 mm. 0.0971 gave 0.0728 AgBr. R r = 31.90. 0.1424 ,, 0.1070 ,, ,, = 31.97. The diazoxides, which are anhydrides of ortho- and paradinzo- 11 4 3 . C,,H,BrN,O requires Br = 32.12 ; K J= 11.28 per cent.HOMONUCLEAL TRI-DERIT'ATIVES OF NAPHTHALENE . 909 phenols, have long been known, and were first prepared by the action of nitrous acid on or.thoamidophenols containin: acid subs tituents i l l the aromatic nucleus (Griess, Annalen, 1860, 113, 212 ; Schmitt and Glut,z, BET., 1869, 2, 52 ; Wagner, Be).., 1874, 7, 1270 ; Bob mer, J. pr. Chem., [ a ] , 1881, 24, 460 ; Lampert, ibid., 1886, 33, 375 ; Kunze, Ber., 1888, 21, 3333 ; Conrad and Limpach, ibid., 1978).Diazoxides of the naphthalene series have also been recently obtained by the oxidation of a- and P-diazonaphthalene in alkaline solution with potassium ferricyanide (Bamberger, Ber., 1894, 27, 67Y), and by the diazotising of certain dinitro-P-naphthylamines, during which process one of the NO,-groups is displaced (Gaess and Ammel burg, Ber., 1894, 27, 2211). The diazoxide, described above, was obtained by u s and identified in 1892 as a,-bromonnphthalene-P,-diaz-xl-oxide. Its formation is best explained by the following scheme, in which the free diazo-compound is represented as taking part in the process of inner condensation with the elimination of bromine.The iso- diazo-form is inadmissible in this case, as the transformation occurs in the presence of excess of strong sulphuric acid. This view of the formation of the diazoxide is confirmed by the presence of bromohgdric acid in the mother liquor after the crystal- line deposit has been removed by filtration. The compound was further characterised by bromination and reduction. When a solu- tion of bromine in glacial acetic acid is added in excess to a solu- tion of the diazoxide in the same solvent, nitrogen is evolved, aiid on allowing t o stand for some hours a crjstalline deposit gradually forms. After repeated crystallisation from glacial acetic acid, the product was obtained pure, and proved t o be dibromo-x-naphth aqui- none, m. p. 2 1 6 O . " 0.1648 gave 0.1963 AgBr.C,,H,Br,O, requires R r = 50.63 per cent. The characteristic anilide crystallising in red scales melting at 190" was also prepared. The formation of dibromo-s-naphthaq ninone from The corresponding dihydro-deriva- tive obtained by reduction gives a diacetyl (m. p. 238"), and not a inonacetS1 derivative on acetyvlation with sodium acetate and acetic anhydride as stated in the paper referred to (p. 810). 4 repetition of the analysis has led us to this conclu- sion, which is quite in harmony with tlie non-phenolic character of the compound. Br. = 50.68. * Trans., 1890, 809 (Veldola and Hughes). 3 P 2910 MELDOLA AND STREATFEILD : the diazoxide by the action of bromine, is certainly a point of some interest, becaiise the q B r atom must be displaced under the in- fluence of the same element exerted as an oxidising agent.I n fact, the facility with which a-substituents can be removed from the naphthalene ring, especially when the neighbouring P-position is also substituted, is quite remarkable, as is seen by the displacement of t h e bromine-atom in the formation of the diazoxide, and even more strikingly in the displacement of the N02-group in the method of Gaess and Ammelburg above re€erred to. An illustration of the same point is furnished by Liebermann and Scheiding's original method of preparing /3-naphthylamine, now of historical interest only, in which nitro-8-bromo-4-naphthalene loses its bromine on reduc- tion with tin and hydrochloric acid (Annakn, 1876, 183, 253). From considerations such as the foregoing, it might have been expected that our bromodiazoxide would lose its bromine-atom on energetic reduction, and thus give 2 : 1-amidonaphthol. This eon- clusion has been borne out by experiment.Some of the compound was reduced by boiling in alcoholic solution with tin and hydro- chloric acid ; the solution was filteretl, the alcohol evaporated off, and the amidonaphthol precipitated a s hydrochloride by adding excess of strong hydrochloric acid. The white precipitate was collected, 1-8- dissolved in water, and re-precipitated by hydrochloric acid, the operation being repeated till the compound was practically lfree from tin salts. The substance had all the properties of the expected amido- naphthol. When basified by ammonia and exposed to the air, the 0 violet colour of naphthaquinoneimide, C,,H,<kH, made its a,ppear- ante.A solution of the hydroch!oride, when warmed with ferric chloride, gradually deposited orange crystals of a-dinaphthyldi- qninone, t8he latter being identified by its characteristic basic tetrani- Iicle ; ni. p. 248-250" (Korn, Ber., 1884, 17, 3022j. ChZoyobromo-/3-mphthylamine, CloH6*C1*NH2*Br = 1 : 2 : 4, nz. 2). 102-103C.-1n the previous paper (Trans., 1892, 768) this compound was only provisionally described. We have since prepared i t in larger quantities, arid by repeated crystallisation, first from dilute, a d finally from absolute alcohol, we have obtained it in the form of white, silky needles melting a t 102-103°. It is devoid of basic properties, like the corresponding dibromo-p-naphthjlamine. The acetyl deriyat ive has the melting point (218') already assigned. As the nitrogen only had been determined in the former preparation, we give the result of determining the halogens :- 0.1030 gave 0.1329 AgCl + AgBr.C1 + Br = 44.94. C,,Il~CIBr.NH, requires C1 + Br = 45.03 per cent.HOJIONUCLEAL TRI-DERIVATIVES OF NAPHTHALENE. 91 X In order to further characterise the substance, the benzoyl deriva- tive was prepared by agitating the base suspended in water with benzoyl chloride, and adding caustic soda solution, drop by drop, till the transformation into the benzoyl derivative was complete. After crystallisation from alcohol the compound consists of beautiful silvery, flattened needles. N = 3.98. 0.1264 gave 4.3 C.C. moist nitrogen at 14' and 757.2 mm. The pure compound has a melting point of 185-186".C,,H,ClBr*NH-C,H,O requires N = 3.88 per cent.. Action of Nitrous acid o n Chlorob?.omo-p-Na~ktlLy lamine. The products in this case vary according to the conditions of the experiment. When the base is dissolved in alcohol and sodium nitrite added to the cold solution, an ochreous crystalline substance separates out, and a further crop of the same compound is obtained hy diluting the filtrate with water, This substance proved to be a diazoamido-compound. It was purified by crystallisation from boiling to1 uene, and then formed yellowish needles having a decomposing point of about 205--210°. 0.1452 gave 10.25 C.C. moist nitrogen at 21.5O and 750 mm. N = 7.91. 0.1392 ,, 0.1762 AgCl + AgBr. C1 + Br = 44.10.0.1544 ,, 10.75 C.C. 9 , 18.5' ,, 758.8 ,, N = 8.02. The formula requires N = 8-01 and C1 + Br = 44.08 per cent. The diazoamido-compound has the following constitution :- c1 c1 I t is more stable than the majority of the diaxoamido-compounds, but, i t is now well kiiown that the accumulation of acid radicles in the molecules increases the stability to a remarkable extent (Zettel, Rri-., 1893, 26, 2471 ; and Herschmann, Bey., 1894, 27, 767). The compound is decomposed on boiling with dilnte sulphuric acid (about equal volumes of strong acid and water), the products being nitrogen, chlorobromonaphthylamine, and a resinons substance which could not be crystallised. When chlorobromo-/I-naphthylnmine is diazotised in glacial acetic acid in the presence of strong sulphuric acid, the decomposition follows the same course as in the case of dibromo-/3-naphthylamine under similar conditions, the diazoxide, C,oH,Br< I (decomposing 0 N,912 MELDOLA AND STREATFEILD : point, 148-151") being formed.In glacial acetic acid only, there is produced, by the action of sodium nitrite, a mixture of diazoamide and diazoxide. Under no conditions has it been found possible to replace the NH2-group by hydroxyl by the diazo-reac tion. Hornonticleal Tyi-dericatiws cowtaiiaing Iodine. In a paper published by one of us 10 years ago (Trans., 1885, 47, ,523), a nitroiodoacetnaphthalide, and the corresponding nitroiodo- naphthol, were described. These compounds were obtained by a very laborious method, and only in small quantity, owing to the bad yield.We have now to describe a more direct method of preparing these derivatives, which has enabled us to obtain them in considerable quantity, and to characterise them more fully than was possible a t tile time of the earlier work. a-Acetnaphthalide is best converted into the iodo-derivative by the action of the calculated quantity of iodine monochloride, both substances being dissolved in glacial acetic acid. On allowing to stand for some days, iod-a-acetnaphthalide separates out as a white, crystalline pulp ; the separation of this compound takes place more rapidly if the solution is slightly warmed. The siibstance has the properties described in the former paper ; the melting point was found t o be 197" (196" in a previous paper). A s no analysis was formerly given, we add the following. N = 4.49.0.2299 gave 8.9 C.C. moist nitrogen at 16" and 758.1 mm. Cl,,HJ*NH*C2H30 requires N = 4.51 per cent. Nitroiodo-a-acetonuplathalide, CloH5*NO2*J*NH*C2H30 = 2 : 4 : 1. -This substance is best prepared by covering pure iod-z-acet- naphthalide with glacial acetic: acid, and t'hen adding about double the calculated quantity of fuming nitric acid, of sp. gr. 1.5, diluted i v i t h an equal volume of acetic acid. The solution gets warm enough on stirring to dissolve up the iodo-derivative, and the nitroiodo-com- pound separates out in a crystalline form on allowing the solution to stand. It is better not to apply heat as described in the earlier method, since there is a tendency under these circumstances for the iodine to become partly replaced by the N02-group, and tile resulting product is thus liable to be rendered impure by admixture with dinitro-a-acetnaphthalide, which is easily formed from the nitroiodo- derivative by the action of excess of nitric acid on the latter, espe- cially when the nitric acid solution is heated.Pure nitroiodo-a-acetnaphthalide forms pale, straw-coloured needles, having a melting point of 242", after repeated crystallisation from glacial acetic acid (melting point of impure substance formerly given as about 236").HOJIOSUCLEAL TRI-DERIVATIVES OF SAPHTHALENE. 913 0.0891 gave 6.1 c.c. moist nitrogen at 12.5" and 756.7 mm. 0.0815 ,, 0.0.538 Agl. I = 35-61. N = 8.06. The formula requires N = 7.S8 ; I = 35-58 per cent. The difficulty of hydrolysing this compound wit>hout at the same time removing iodine, as mentioned in the former paper, has been amply confirmed, and we have been unable to obtain the nitroiodo- 2:-naphthylamine, or the corresponding metanitroiodonaphthalene.Nit?.oiodo-cc-?~npht~oZ, C,oH,*NO,*I*OH = 2 : 4 : 1.-The preparation and properties of this compound have been described in the paper of 1885 (Zoc. cit., p. 524). We find that by repeated crystallisation from glacial acetic acid, the melting point becomes 1503, but the compound begins t o shrink before it melts at 147-148". 0-1083 gave 4-35 C.C. moist nitrogen at 21Oand 767.6 mm. N = 4.61- The formula requires N = 4.47 per cent. In order to further characterise this compound, the potassium salt It consisted of orange needles, which 0.2404 dried at 100--110" till constant in weight lost 0.0124 = 0.2280 gave 0.0550 K,SO,. was prepared and analysed. were crystallised from boiling water. HZO, 5-07'. K = 10.81. 11.05 per cent. The formula CloH5*N@2*I.0K,H20 requires H,O = 4.85 and K = The ethyl ether, CloH5-NO2*I~0 C2H5, was also prepared by treating the silver salt (a brick-red powder) with ethyl iodide. It forms pale yellow, flattened needles or scales when crystallised from alcohol, in which it is extremely soluble. In conclusion, we may add that iodine chloride readily forms an iodine derivative of P-acetnaphthalide, which is now under investiga- tion. The foregoing research has been taken part in by several of our students, and we desire to express our thanks more particularly to Jlessrs. F. B. Burls, H. W. Younger, and E. It, hndre-tvs. The melting point is 104----105O. Finsbury Technical C ~ l l e g e .