Efficient One-Pot Synthesis of Benzothiazole Compounds From Vinamidinium Salts.

In this study, the condensation reaction between vinamidinium salts and Z-2-hydrazineylidene-3-methyl-2,3-dihydrobenzo[d]thiazole is described for the synthesis of 1,3-bis((3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazineylidene)propan-2-ol (BBTA) or 1-((1Z,3E)-1-(dimethylamino)-3-(((Z)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazineylidene)prop-1-en-2-yl)pyridin-1-ium (DMBT). A noteworthy aspect of the synthesis of these derivatives is that the structure of the vinamidinium salt acts as the determining factor for the type of product formed. Specifically, phenyl-substituted vinamidinium salts predominantly lead to the formation of symmetric BBTA derivatives, whereas pyridinium-based vinamidinium salts favor the production of asymmetric DMBT compounds. The reaction was carried out in the presence of triethylamine as the base and acetonitrile as the solvent under catalyst-free conditions. The structure of the new products was confirmed based on their spectral data, including 1H NMR, 13C NMR, IR, mass spectrometry, high-resolution mass spectrometry and X-ray analysis.