2-Heterocyclylmercaptoalkyl penems were synthesized and their in vitro potency was established. The compounds exhibit moderate to strong antibacterial activity against various Gram-positive and Gram-negative bacteria. Their antimicrobial activity is related to the nature of the heterocycle, the length of the hydrocarbon spacer between the 2-position of the penem nucleus and the mercapto group, and the substitution pattern of the C-6 position of the penem skeleton.
