POLYMETHYNE DYES WITH THIAZOLO (3,2-a)PYRIMIDINE AND PYRIMIDO(2,1-b)BENZTHIAZOLE SALTS WITH A TRIFLUOROMETHYL GROUP IN THE PYRIMIDINE CYCLE.

Abstract

There are synthesized various types of polymethine dyes from trifluoromethylthiazo­lo(3,2-a)pyrimidinium and trifluoromethyl­pyrimido(2,1-b)benzthiazolium perchlorates various types of polymethine dyes were obtained – styryls, monomethinecyanines, symmetrical and asymmetrical carbocyanines, merocyanines. The absorption maxima and their intensities are determined for each dye, absorption characteristics curves and elemental analysis data for Carbon, Hydrogen and Sulfur are provided. As a result of the dyes absorption maxima analysis containing a tri­-fluoromethyl group in the pyrimidine ring and synthesized in this reaserch with the absorption maxima of dyes without a trifluoromethyl group in the pyrimidine ring, the bathochromic effect of the trifluoromethyl group on the dyes absorption maxima was established. The phenyl in the fifth position of the thiazole ring causes a bathochromic shift of the dye absorption maximum. There are characteristics of the absorption curve. The α- and γ-deriva­tives of monocyanines have a significant difference. The curve is flat with one absorption maximum for α-derivatives.The curve is narrower and contains two absorption maxima for γ-derivatives. The absorption curves of merocyanines also contain two maxima. The results of elemental analysis for Carbon, Hyd­rogen and Sulfur are presented. The resulting polymethine dyes are easily synthesized from thiazolo(3,2-a)pyrimidinium and pyramido­(2,3-b)benzthiazole in an acetic anhydride me­dium with product output at least 41%. The styrene product output are 53–93%. Synthesized dyes are crystallized from acetic anhydride. Symmetrical carbocyanines are crystallized from dimethylformamide.