title: Preparation, identification, and quantitative NMR determination of silyl derivatives of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid.
abstract: A rapid and accurate method for the quantitative determination of the extent and ratio of amino and carboxyl group trimethylsilylation of 6-aminopenicillanic acid, 7-amino-3-methyl-delta3-cephem-4-carboxylic acid, and 7-amino-3-acetoxymethyl-delta3-cephem-4-carboxylic acid is presented. The method utilizes NMR spectroscopy and is based on the difference in chemical shifts between N-trimethylsilyl and O-trimethylsilyl groups or, in cephalosporin derivatives, between the methyl group in the 3-position and free amino resonances. The spectra of the N,O-bis(trimethylsilyl) derivatives are discussed.
mesh_terms: D002511:Cephalosporins / Q000032:analysis* / Q000138:chemical synthesis; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D010397:Penicillanic Acid / Q000032:analysis* / Q000138:chemical synthesis; D014297:Trimethylsilyl Compounds / Q000032:analysis / Q000138:chemical synthesis
chemical_list: D002511:Cephalosporins; D014297:Trimethylsilyl Compounds; D010397:Penicillanic Acid