title: Synthesis of tritium-labelled isopenicillin N, penicillin N and 6-aminopenicillanic acid.
abstract: 1. Phenoxymethylpenicillin sulphoxide 4-methoxybenzyl ester was labelled with 3H in its 2-beta-methyl group. Its specific radioactivity was 362 mCi/mmol. 2. Removal of the side chain of this compound yielded the corresponding ester of 6-aminopenicillanic acid sulphoxide and coupling of the latter with the appropriate protected alpha-aminoadipic acid gave 4-methoxybenzyloxycarbonylisopenicillin N sulphoxide di-4-methoxybenzyl ester or the corresponding derivative of penicillin N. 3. Removal of the protective groups by hydrogenolysis and reduction of the sulphoxide group yielded 3H-labelled isopenicillin N or penicillin N. 4. 3H-labelled phenoxymethylpenicillin sulphoxide was obtained by hydrogenolysis from its 4-methoxybenzyl ester. Reduction of its sulphoxide group and subsequent removal of the side chain gave 3H-labelled 6-aminopenicillanic acid.
mesh_terms: D015074:2-Aminoadipic Acid / Q000031:analogs & derivatives; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D004586:Electrophoresis; D007553:Isotope Labeling; D010397:Penicillanic Acid / Q000138:chemical synthesis; D010404:Penicillin V / Q000031:analogs & derivatives / Q000138:chemical synthesis; D010406:Penicillins / Q000138:chemical synthesis*; D012588:Scintillation Counting; D014316:Tritium
chemical_list: D010406:Penicillins; D014316:Tritium; D015074:2-Aminoadipic Acid; D010397:Penicillanic Acid; D010404:Penicillin V