Process for preparing 3-methylene cephalosporins
AssigneeE. R. Squibb & Sons, Inc.
InventorEric M. Gordon
Life of this patent
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Abstract
Photolysis of azetidin-2-one derivatives having the formula ##STR1## wherein R.sub.1 is acyl, R.sub.2 is hydrogen or .alpha.-methoxy, R.sub.3 is hydrogen, alkyl, 2,2,2-trichloroethyl, trimethylsilyl, diphenylmethyl, benzyl, 4-methoxybenzyl, or 4-nitrobenzyl, and R.sub.4 is an aromatic heterocyclic group, yields 3-methylene cephalosporins.
Claims4
A process for the conversion of an azetidin-2-one derivative having the formula ##STR10## to a 3-methylenecepham having the formula ##STR11## which comprises the photolytic conversion of the azetidin-2-one derivative to the 3-methylenecepham by exposing the azetidin-2-one derivative to a light source emitting light of a wavelength that the azetidin-2-one derivative absorbs;
- wherein R.sub.1 is acyl, R.sub.2 is hydrogen or .alpha.-methoxy, R.sub.3 is hydrogen, alkyl, 2,2,2-trichloroethyl, trimethylsilyl, diphenylmethyl, benzyl, 4-methoxybenzyl, or 4-nitrobenzyl, and R.sub.4 is an aromatic heterocyclic group.
A process for the conversion of an azetidin-2-one derivative having the formula ##STR12## to a 3-methylene cepham having the formula ##STR13## which comprises irradiating with ultraviolet radiation, in an organic solvent, the azetidin-2-one derivative wherein R.sub.1 is acyl, R.sub.2 is hydrogen or .alpha.-methoxy, R.sub.3 is hydrogen, alkyl of 1 to 4 carbon atoms, 2,2,2-trichloroethyl, trimethylsilyl, diphenylmethyl, or 4-methoxybenzyl, and R.sub.4 is an aromatic heterocyclic group.
Dependencies are inferred from the claim text.