Synthesis of Some New 5-Arylazothiazole Derivatives as Disperse Dyes for Dyeing Polyester Fibers

A series of 5-arylazo-2-(arylidenehydrazino)-2-th iazo lin -4-one dyes 3 and 4 was prepared by cyclocondensation of hydrazonoyl bro mides 2 with various thiosemicarbazone derivatives 1. While the synthesis of 3-amino-N-(5-arylazo-2-thiazo lyl)-thieno(2,3-b)pyrid ine-2-carbo xamide dyes 8 was achieved by the reaction of 2-(N-chloroacetyl)-5-ary lazo-thiazo le derivatives 5 with 4,6-dimethyl-2-mercaptonicotinonitrile fo llowed by heterocyclizat ion of the obtained sulfide derivatives 7 in a solution of ethanol containing sodium etho xide. These dyes were applied as disperse dyes for dyeing polyester fibers and their characteristics and fastness properties have been measured. The dyed fibers exh ibit very good to excellent washing, perspiration and sublimat ion fastness properties, with little variation in good to excellent rubbing and light fastness.