Disazo dyes containing pyrazole and benzothiazole moieties: synthesis, characterization, absorption characteristics and tautomeric structures

摘要

Eight newly synthesized disazo disperse dyes containing benzothiazole and pyrazole moieties were prepared by diazotization of 2-aminobenzothiazole, coupling with 3-aminocrotononitrile as active methylene, cyclization reactions with hydrazine hydrate and phenyl hydrazine, diazotization again and finally coupling with dimedone, dioxane, 1-methyl imidazole and 2-methyl imidazole, respectively. Their structures were characterized with spectroscopic methods (FT-IR, H-1-NMR, C-13-NMR) and solvatochromic properties were studied with UV-Vis spectroscopy in different solvents. Tautomeric structures of synthesized dyes were also examined in detail.