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

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 mono hydrate 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 H-1 NMR spectroscopic methods and elemental analysis. Furthermore, the absorption profiles of the dyes in different solvents and in acidic and basic media were investigated. (C) 2018 Published by Elsevier B.V.