Synthesis and antimicrobial activity of new 2-phenylethynylbenzothiazoles and related salts.

New 2-phenylethynylbenzothiazoles were synthesized by coupling reaction between 2-iodobenzothiazole and substituted phenylacetylenes under palladium catalysis. The modified Wittig reaction was used to prepare the substituted phenylacetylenes from corresponding benzaldehydes. 2-Phenylethynylbenzothiazoles were next quarternized with trimethyloxonium tetrafluoroborate to 3-methylbenzothiazolium salts. Antimicrobial in vitro activities were determined for all new compounds.