Process for converting 6,6-disubstituted penicillanic acid derivatives to the 6-.beta.-congeners
AssigneePfizer Inc.
InventorsMichael S. Kellogg, Ernest S. Hamanaka
Life of this patent
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Abstract
6-.beta.-Substituted penicillanic acids and derivatives thereof as useful enhancers of the effectiveness of several .beta.-lactam antibiotics against many .beta.-lactamase producing bacteria, and 6-.beta.-substituted penicillanic acid derivatives wherein the carboxy group is protected by a conventional penicillin carboxy protecting group as useful intermediates leading to said synergistic agents. A process for converting 6,6-disubstituted penicillanic acid derivatives to the corresponding 6-.beta.-substituted penicillanic acid congeners.
Claims18
A proceess for the preparation of a compound selected from those of the formula ##STR34## wherein R.sub.15 is selected from the group consisting of fluoro, chloro, bromo, iodo, alkoxy having from one to four carbon atoms and alkylthio having from one to four carbon atoms;
- n is an integer of from 0 to 2;
- and R.sub.13 is selected from the group consisting of hydrogen and ester-forming residues readily hydrolyzable in vivo which comprises reacting a compound of the formula ##STR35## wherein X is selected from the group consisting of chloro, bromo and iodo;
- and R.sub.19 is selected from the group consisting of ester-forming residues readily hydrolyzable in vivo and conventional penicillin carboxy protecting groups, with an organotin monohydride at about 0.degree.-110.degree. C., followed by removal of R.sub.19 when it is a conventional penicillin carboxy protecting group, with the proviso that when said R.sub.19 is a conventional penicillin carboxy protecting group n is an integer of from 0 to 1.
A process for the preparation of a compound selected from those of the formula:
- ##STR36## wherein R.sub.15 is selected from the group consisting of fluoro, chloro, bromo, iodo, alkoxy having from one to four carbon atoms and alkylthio having from one to four carbon atoms;
- n is an integer from 0 to 2;
- R.sub.13 is an ester group which comprises reacting a compound of the formula:
- ##STR37## wherein X is selected from the group consisting of chloro, bromo and iodo;
- R.sub.19 is an ester group with a tri-alkyl tin hydride.
Dependencies are inferred from the claim text.