title: Synthesis of 2 alpha-methyl- and 2 beta-methyl-3-(substituted methyl)cephalosporins, and 2,3-diexomethylenecepham.
mesh_terms: D002511:Cephalosporins / Q000138:chemical synthesis* / Q000494:pharmacology
chemical_list: D002511:Cephalosporins; C039206:2,3-di-exo-methylencepham