Merck + Co., Inc.

F Aileen Bouffard

Burton G Christensen

Thomas N Salzmann

David B Johnston

Nathan G Steinberg

A stereospecific process for preparing 3-trans-R-trisubstituted silyloxyethyl substituted azetidinones useful as intermediates for preparing penems and carbapenems is provided wherein a 3-unsubstituted azetidinone is treated with a strong base and a trisubstituted silylmethyl ketone to form 3-trans-S-[1-trisubstituted silyl-1-hydroxy]ethylazetidinone followed by rearrangement of this resulting carbinol by treatment with an alkali metal alkoxide and a proton source.

Process for the stereocontrolled silyloxyethylation of azetidinones

Disclosed are substituted azetidinones (1) which are useful in the preparation of 1-carba-2-penem-3-carboxylic acids (I): ##STR1## wherein R is hydrogen or a blocking group and R.sup.1, R.sup.2 and R.sup.3 are, inter alia, independently selected from the group consisting of hydrogen, alkyl, aryl, and aralkyl. Such 1-carba-2-penem-3-carboxylic acids and their pharmaceutically acceptable salt, ester and amide derivatives are useful as antibiotics.

Substituted azetidiones

Disclosed are Schiff's base derivatives of the antibiotic thienamycin, which has the following structure: ##STR1## Such compounds and their pharmaceutically acceptable salt, ester and amide derivatives are useful as antibiotics. Also disclosed are processes for the preparation of such derivatives, pharmaceutical compositions comprising such derivatives, and methods of treatment comprising administering such derivatives and compositions when an antibiotic effect is indicated.

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Scotch Plains, NJ, United States of America

F Aileen Bouffard