When penicillin (S)-S-oxide esters are treated with triethylamine and acetonitrile containing DzO, both epimerization and deuteration at the 6-position occurs. This reaction is found to be a convenient method for the preparation of 6-deuteriopenicillins. 6-Deuteriobenzylpenicillin (S)-S-oxide benzyl ester (containing more than 95% D in the 6-position) was obtained from the (S)-S-oxide of penicillin G benzyl ester. Deoxygenation of the sulfoxide followed by catalytic debenzylation gave penicillin G deuterated in the 6-position. A kinetic study of deuterium incorporation and epimerization at C-6 was carried out for the (S)-S-oxide of penicillin V benzyl ester and for its 6-epimer. Deuteration was found to be faster than epimerization when the sulfoxide with the natural configuration was used as starting material. In the experiment starting with the 6-epimer, epimerization is faster than deuteration. A revised mechanism for the epimerization and deuteration of penicillin S-oxide esters is proposed.

Die Lactamspaltung der Penicillansäure (III) mit KOH liefert die isomeren Carboxymethylthiazolidincarbonsäuren (I) und (II), mit Alkalialkoholaten (IV) und (III) werden die Halbester (V) und (VI) erhalten, die mit α‐Diazotoluol (VII) zu den Benzylestern (VIII) und (IX) reagieren.

Die Herstellung deuterierter Penicilline (b‐Reihe) aus den entsprechenden Penicillinen (Ia)‐(IVa) durch Behandlung mit Triethylamin, Acetonitril und Deuteriumoxid wird beschrieben.