title: Preparation of 6-aminopenicillanic acid--chemical vs enzymatic methods.
mesh_terms: D000667:Ampicillin / Q000138:chemical synthesis; D010397:Penicillanic Acid / Q000138:chemical synthesis* / Q000031:analogs & derivatives
chemical_list: D000667:Ampicillin; D010397:Penicillanic Acid; C004408:aminopenicillanic acid