Synthesis, structural analysis, and absorption properties of disperse benzothiazol-derivative mono-azo dyes

Abstract

A series of carbocyclic amines was reacted with 3-aminocrotonitrile to give the 2-arylhydrazone-3-ketiminobutyronitriles 1(a–m). Separately, 2-aminobenzothiazole was treated with hydrazine monohydrate to afford 2-hydrazinobenzothiazole. Then, compounds 1(a–m) were reacted with 2-hydrazinobenzimidazole under reflux in ethanol to give the 1-(1,3-benzothiazol-2-yl)-3-methyl-4-arylazo-5-aminopyrazole compounds 2(a–m). The structures of the synthesized compounds were investigated using FT-IR and 1H NMR spectroscopic methods and elemental analysis. Furthermore, the absorption profiles of the dyes in different solvents and in acidic and basic media were investigated.