GB442185A - The manufacture of indigoid vat dyestuffs - Google Patents

Abstract

5 - Alkoxy - 6 - methyl - 7 - chlor or 5-alkoxy-6 - chlor - 7 - methyl - hydroxythionaphthenes or reactive 2-derivatives thereof are condensed with isatins of the benzene or naphthalene series or reactive 2-derivatives thereof or hydroxythionaphthenes other than alkoxychlormethylhydroxythionaphthenes or reactive 2-derivatives thereof, the two components being in different states of oxidation. In examples: (1) 5-methoxy-6-methyl-7-chlorhydroxythionaphthene is condensed with 4-methyl-6-chlor-2 : 3-diketodihydrothionaphthene-2-p-dimethylaminoanil or the p-dimethylaminoanil of the former is condensed with 4-methyl-6-chlorhydroxythionaphthene; 2 : 3-naphthoxythiophen may be used as the second component; (2) 2 : 1-naphthisatin-a -chloride, prepared in situ, is condensed with 5-methoxy-6-methyl-7-chlorhydroxythionaphthene; (3) 5-methoxy-6-chlor - 7 - methylhydroxythionaphthene is condensed with 2 : 1 - naphthoxythiophen p - dimethylaminoanil or 8 - chlor-1 : 2 - naphthoxythiophen-p-dimethylaminoanil. 5 - Alkoxy - 6 - methyl - 7 - chlor and 5-alkoxy-6-chlor-7-methylhydroxythionaphthenes may be prepared from the corresponding alkoxychlormethylbenzenesulphonic acids by way of the sulphochlorides, mercaptans and thioglycollic acids. Thus, 5 - methoxy - 6 - methyl - 7 - chlorhydroxythionaphthene of example 1 may be made from 1-methyl-2-methoxy-6-chlorbenzene by treating with chlorsulphonic acid, reducing, condensing with chloracetic acid and effecting ring closure after conversion into the acid chloride. 5-Methoxy-6-chlor-7-methylhydroxythionaphthene may be made in a similar manner from 2-amino-3-methoxy-1-methylbenzene-6-sulphonic acid after replacing the amino group by chlorine. (Sandmeyer's reaction).