Synthesis and solvatochromic properties of 3,6-bis-hetarylazo dyes derived from pyrazolo[1,5-a]pyrimidine

Novel, symmetrical and asymmetrical, 3,6-bis-hetarylazo-2,5,7-triaminopyrazolo[1,5-a]pyrimidine heterocyclic disazo dyes were synthesized via cyclization from substituted hetarylazomalononitrile precursors with various substituted hetarylazopyrazole compounds. The synthesized heterocyclic disazo dyes were characterized using FT-IR, 1H NMR, mass spectroscopy and elemental analysis. The solvatochromic effects of the dyes in various organic solvents were studied.