cephems

https://doi.org/10.1351/goldbook.C00941
2,3-Didehydrocephams: 5-thia-1-azabicyclo[4.2.0]oct-2-en-8-ones.
See:
cephalosporins
,
cephams
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1327 [Terms] [Paper]