natural product fundamental parent penam (5R)-4-thia-1-azabicyclo[3.2.0]heptan-7-one 129.025 129.18122 Beilstein:4374479 C5H7NOS CHEBI:35991 Compound comprising a beta-lactam ring fused to a saturated 5-membered ring containing one sulfur atom. InChI=1S/C5H7NOS/c7-4-3-5-6(4)1-2-8-5/h5H,1-3H2/t5-/m1/s1 WSHJJCPTKWSMRR-RXMQYKEDSA-N Wikipedia:Clavam [H][C@@]12CC(=O)N1CCS2 chebi_ontology clavam clavams penam penams