Ultraviolet-mediated antibiotic activity of synthetic thiophenes and their acetylenic derivatives

Thirty-one thiophene derivs., with various substituents, were synthesized and their phototoxicities to six microorganisms were compared with those of the naturally occurring photodynamic compd., α-terthienyl.  The test organisms were: Staphylococcus albus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Saccharomyces cerevisiae, and Candida albicans.  Most of these compds., some of which also occur naturally, displayed phototoxicity towards the microorganisms, and several were more potent than α-terthienyl.  The most active compds. contained 1-alkynyl groups linked to a thiophene or 2-phenylthiophene in the α-position, or to a 2,2'-bithienyl system in the 5-position.