Facile Synthesis of Heterocycles via 2-Picolinium Bromide and Antimicrobial Activities of the Products

摘要

The 2-picolinium N-ylide >4, generated in situ from the N-acylmethyl-2-picolinium bromide >3, underwent cycloaddition to N-phenylmaleimide or carbon disulfide to give the corresponding cycloadducts >6 and >8, respectively similar reactions of compound >3 with some electron-deficient alkenes in the presence of MnO2 yielded the products >11 and >12. In addition, reaction of >4 with arylidene cyanothioacetamide and malononitrile derivatives afforded the thiophene and aniline derivatives >15 and >17, respectively. Heating of picolinium bromide >3 with triethylamine in benzene furnished 2-(2-thienyl)indolizine (>18). The structures of the isolated products were confirmed by elemental analysis as well as by ¹H- and ¹³C-NMR, IR, and MS data. Both the stereochemistry and the regioselectivity of the studied reactions are discussed. The biological activity of the newly synthesized compounds was examined and showed promising results.