GB417497A - Manufacture of ortho-amino-azo-compounds - Google Patents

Abstract

o-Aminoazo compounds are made by subjecting an o-nitroazo compound of the general formula (o-) NO2--R--N = N--R1 wherein R = a benzene residue and R1 = a benzene residue which contains a negative substituent, such as halogen or the nitrogroup, in o-position to the azo group, to the action of a reducing agent. In examples, the following o-aminoazo compounds are made by reducing the corresponding nitro compounds with aqueous alcoholic sodium sulphide: (1) 2<1>-chloro-2-aminoazobenzene; (2) 2<1> : 4<1>-dichloro-2-aminoazobenzene; (3) 4 - methyl - 2 - amino - 2<1> : 4<1> - dichloroazobenzene; (4) 2<1>-nitro-2-aminoazobenzene. The Specification as open to inspection under Sect. 91 comprises also the preparation of 2<1>-bromo-2-aminoazobenzene, 2<1> : 4<1>-dibromo-2-aminoazobenzene, 4 - methoxy - 2 - amino - 2<1> - chloroazobenzene, 4 - methoxy - 2 - amino - 2<1> - chloro - 4<1> - methoxyazobenzene, 5 - methyl - 4-methoxy - 2 - amino - 2<1> : 4<1> - or 2<1> : 5<1> - dichloroazobenzene, 5-methyl-4-methoxy-2-amino-2<1>-nitro-4<1>-chloro- or 4<1>-methoxy- or 4<1>-methylazobenzene, 5 - methyl - 4 - ethoxy - 2 - amino - 2<1> : 5<1> dichloroazobenzene, 5 - chloro - 4 - methoxy - 2 - amino - 2<1> : 4<1> - dichloroazobenzene, 4 : 5 - dimethoxy-2-amino-2<1> : 4<1>-dichloroazobenzene. This subject-matter does not appear in the Specification as accepted.