Improvements in and relating to monoazo dyes

摘要

Water-insoluble monoazo dyes of formula in which X is a hydrogen atom or an alkyl, phenyl or substituted phenyl group, Y is a hydrogen atom or an alkyl or alkoxy group, Z is a hydrogen or halogen atom or an alkyl or alkoxy group, R1 is a hydrogen atom or an alkyl group, and R2 is an alkyl group containing one or two -O-acyl groups are prepared by diazotizing a 2-amino-5-nitro-thiazole of formula and coupling with an amine of formula all symbols being as above. Alternatively a dye of formula in which R3 is an alkyl group having one or two hydroxyl groups is esterified with an aliphatic or aromatic carboxylic acid or a functional derivative of either (acid chlorides and anhydrides). The dyes give blue-violet colours on hydrophobic materials.