GB369453A - Manufacture of hydroxy-benzo-carbazoles - Google Patents

Abstract

Hydroxybenzocarbazoles of the general formula <FORM:0369453/IV/1> wherein one y = H, the other y = OH, X = hydrogen or alkyl, the nuclei R1 and R2 may contain substituents and the nucleus R2 may be condensed with a further nucleus are made by heating an arylhydrazine in the presence of mineral acid with an a -b -dihydroxynaphthalene-bisulphite addition compound. Phenyl-, naphthyl- and N-alkyl-arylhydrazines (asymmetrical) are specified. The products are valuable for the manufacture of azo-dyestuffs in substance or on the fibre. In examples (1) 2<1>-hydroxy-7 : 8-benzocarbazole is made from phenylhydrazine hydrochloride and the addition compound of 1 : 6-dioxynaphthalene and sodium bisulphite in sulphuric acid solution, (2) N-methyl-2<1>-hydroxy-7 : 8-benzocarbazole is similarly made from N-methylphenylhydrazine, (3) 2<1>-hydroxy-3<1> : 6-dibromo-7 : 8-benzocarbazole is made from phenylhydrazine and the sodium bisulphite addition compound of 4 : 7-dibromo-1 : 6-dioxynaphthalene, (4) 2<1>-hydroxy - 1 : 2 : 7 : 8 - dibenzo - 1<11> - chlorocarbazole is made from 5-chloronaphthylhydrazine and the bisulphite addition compound of 1 : 6-dioxynaphthalene, (5) 3<1>-hydroxy-7 : 8-benzocarbazole is made as in (1) from 1 : 7-dioxynaphthalene, (6) 3-methyl-N-ethyl-3<1>-hydroxy-7 : 8-benzocarbazole is made from N-ethyl-p-methylphenylhydrazine and the addition compound of 1 : 7-dioxynaphthalene. Specification 275,326, [Class 2 (iii), Dyes &c.], is referred to. 4 : 7-Dibromo-1 : 6-dioxynaphthalene is made by treating the sodium bisulphite addition compound of 1 : 6-dioxynaphthalene with bromine in aqueous solution. 5-Chloronaphthylhydrazine is made by reducing the diazo compound of 5-chloro-1-naphthylamine. N-ethyl-p-methylphenylhydrazine is made by nitrosating N-ethylamino-p-methylbenzene and reducing the nitroso compound with zinc powder and acetic acid.