GB451348A - Manufacture of aromatic nitrogen compounds - Google Patents

Abstract

Aromatic amino compounds are obtained by reacting the bisulphite addition product of a hydroxy compound of the benzene series, or of an a -hydroxy compound of the naphthalene or anthracene series, in the form of its free acid, with a free primary amino compound. The process may be effected by reacting the isolated bisulphite addition compound with a salt of the primary amino compound unless the latter contains a free acid group, in which event it may be taken as such. Alternatively, the bisulphite addition product may be produced in aqueous solution and then subjected to the reaction without isolation, but in this case any excess of bisulphite must first be neutralized or eliminated. The reagents may be heated to 100--200 DEG C. in the presence or absence of a diluent, e.g. chlorobenzene, glycerine or dimethylaniline; an addition compound of the reagents is believed to be formed first, and can sometimes be isolated. The bisulphite addition compounds used as starting materials may be prepared by boiling the hydroxy compound with an excess of bisulphite solution and recovering the product by cooling, addition of sodium chloride, or evaporation. In the examples: (1) the bisulphite addition product of 2 : 5-dihydroxynaphthalene is heated with aniline hydrochloride; 5-phenylamino-2-naphthol is obtained; (2) the bisulphite addition product of 1 : 5-dihydroxynaphthalene is heated with aniline sulphate; 5-phenylamino-1-naphthol is obtained; (3) the bisulphite compound of 2 : 8-dihydroxynaphthalene is heated with b -naphthylamine hydrochloride to yield 8-b -naphthylamino-2-naphthol; (4) the bisulphite compound of 1 : 5-dihydroxynaphthalene is heated with benzidine hydrochloride to yield a product of unstated constitution; (5) a -anthrol bisulphite and p-aminophenol hydrochloride yield 4<1>-hydroxy-1-phenylaminoanthracene; (6) resorcinol and aqueous sodium bisulphite are heated, and the excess of bisulphite is then destroyed by gradual addition of hydrochloric acid; the solution is then neutralized, and boiled with aniline hydrochloride; a product which still contains the sulphurous acid residue is precipitated, and this yields diphenyl-m-phenylenediamine when it is boiled with aqueous caustic soda or heated to fusion or warmed in glycerol to about 200 DEG C.; (7) the bisulphite compound of 2 : 8-dihydroxy-3-naphthoic acid (as sodium salt) is heated with p-aminoanisole hydrochloride to yield a product, of unstated constitution, which can be coupled with diazotized bases; (8) the bisulphite compound of 2 : 8-dihydroxy-3-naphthoic acid is heated with anthranilic acid in glycerol containing sulphuric acid; a product believed to be 8-phenylamino-2-napththol-3 : 2<1>-dicarboxylic acid is obtained; (9) resorcinol bisulphite and aniline-m-sulphonic acid are reacted as in example 6 to yield a product of unstated constitution; (10) resorcinol bisulphite and hydrazine hydrate, reacted as in example 6 in the presence of hydrochloric acid, yield m-phenylenedihydrazine; (11) resorcinol bisulphite and phenylhydrazine hydrochloride, reacted as in example 6, yield a product of unstated constitution; (12) a -naphthol bisulphite and p-aminophenol hydrochloride yield a product of unstated constitution.