Natural and synthetic antibiotics containing the 4-thia-1-azabicyclo[3.2.0]heptan-7-one structure, generally assumed to have the 5R
configuration unless otherwise specified. The numbering of the penam skeleton differs from that of the von Baeyer named bicyclic system. Where they differ the von Baeyer numbering is shown in parentheses in the example.
See also: penems
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1356 (https://doi.org/10.1351/pac199567081307)