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Chemical structures of five β-lactam compounds. (a) Ceftiofur; (b) Nitrocefin; (c) Desfuroylceftiofur (DFC); (d) Ampicillin; (e) Clavulanic acid. Thiazolidine, β-lactam, aminothiazole, thiophene, penam, and oxazoline rings—and also methoxyimine and furfural groups—are shown with arrows. The figures were generated with the MarvinSketch v.17.28.0. (Budapest, Hungary).
