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Decomposition of 1-(azidophenyl)-4,6-diamino-1,3,5-triazines 11-13 and their 4-amino-6-(azidoanilino) 1,3,5-triazine isomers 31-33 in trifluoromethanesulphonic acid at 0° led to the introduction of the triflate group (OSO 2 CF 3 ) into the aryl group. This method can be employed to introduce a bulky substituent into the hindered position ortho to the triazinyl substituent. Dimroth rearrangement of 1-(aryl)-4,6-diamino-1,3,5-triazines is best effected in refluxing ethanolic pyridine

Decomposition of 1-(azidophenyl)-4,6-diamino-1,3,5-triazines 11-13 and their 4-amino-6-(azidoanilino) 1,3,5-triazine isomers 31-33 in trifluoromethanesulphonic acid at 0° led to the introduction of the triflate group (OSO 2 CF 3 ) into the aryl group. This method can be employed to introduce a bulky substituent into the hindered position ortho to the triazinyl substituent. Dimroth rearrangement of 1-(aryl)-4,6-diamino-1,3,5-triazines is best effected in refluxing ethanolic pyridine

Das Salz (Ib) ist nicht durch Diazotierung des Amins (Id) und anschliesende Umsetzung mit Na-azid, jedoch aus dem Hydrazin (Ia) durch Diazotieren in guter Ausbeute erhaltlich.

2,4-Diamino-6-aryl-s-triazines (III) have been prepared for examination as potential tumour-inhibitory agents. 2,4-Diamino-6-(2-aminophenyl)-s-triazines (IV) react with formic acid and triethyl orthoformate to form the formylaminophenyl- and ethoxymethyleneaminophenyl-s-triazines respectively, but in formamide 4-aminoquinazolines are produced. Diazotisation of the amines (IV) afforded in certain instances stable diazonium salts (X) which cyclised in base to derivatives of s-triazino[1,2-c][1,2,3]benzotriazine (XI). Replacement of the diazogroup in the s-triazinobenzotriazines (XI) by hydrogen, and by amino-, chloro-, hydroxy- and azonaphthol substituents demonstrates the similarity between the chemical properties of 1,2,3-benzotriazines and diazonium compounds. Reduction of the s-triazinobenzotriazines with stannous chloride in ethanol yielded s-triazino-[1,2-b]indazoles (XIV), which were also formed by cyclo-deamination of the hydrazines (XV) and by thermolysis of the azides (XVII). The s-triazinobenzotriazenes decompose homolytically in boiling nitrobenzene to afford a mixture of isomeric nitrobiphenyls: the mass spectra of the isomers are discussed.

Alkylation of 4-arylamino-1,2,3-benzotriazines with alkyl iodides in ethanol affords the N-2 alkyl iodides which on basification yield the deep-red anhydro-2-alkyl-4-arylamino-1,2,3-benzotriazinium hydroxides. In contrast alkylation in sodium ethoxide solution affords isomeric products substituted at N-2 and N-3. The site of alkylation of the N-2 substituted series has been confirmed by reduction studies; hydrazine in ethanol containing Raney nickel efficiently degrades the triazine ring. The chemical and spectroscopic properties of the red triazines have been investigated.

Benzil reacts with diaminoguanidine nitrate to yield the nitrate salt of benzil mono[(aminoamidino)hydrazone](2). The hydrazone (2) is unstable, and cyclises on melting or in solvents to 5,6-diphenyl-3-hydrazino-1,2,4-triazine (3). Diazotisation of the hydrazone (2) and of hydrazine (3) affords the same product, 6,7-diphenyltetrazolo-[1,5-b]-as-triazine (9) which decomposes in boiling secondary amines to yield substituted 3-amino-5,6-diphenyl-1,2,4-triazines and hydrazoic acid. Both the hydrazone (2) and the hydrazine (3) react with triethyl orthoformate or formic acid to give 6,7-diphenyltriazolo[4,3-b]-as-triazine (16), which was also prepared, unambiguously, from benzil and 3,4-diamino-1,2,4-triazole. Although conditions favourable for Dimroth rearrangement were employed, no such transformations were encountered in the reactions of the bicyclic systems (9) and (16).

A series of 3-substituted-3,4-dihydro-4-imino-1,2,3-benzotriazines (V) have been prepared by cyclization of the appropriate o-cyanophenyltriazenes (IV) in 70% aqueous ethanol or in ethanol containing 2% piperidine. Triazenes with powerful electron-withdrawing substituents cyclize directly to substituted 4-anilino-1,2,3-benzotriazines (VI). Rearrangement of 3-aryl-3,4-dihydro-4-imino-1,2,3-benzotriazines to the isomeric 4-anilino-1,2,3-benzotriazines has been effected in ethanol or in 2N-hydrochloric acid and is facilitated by electron-withdrawing substituents in the aryl nucleus. The contrasting stabilities of 3-benzyl- and 3-phenethyl-3,4-dihydro-4-imino-1,2,3-benzotriazine have been attributed to a steric affect.