Method of preparation of 5,6-dehydropenicillins
AssigneeSnamprogetti S.p.A.
InventorsLuciano Re, Alberto Brant, Luciano Bassignani
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Abstract
A method is disclosed for the preparation of a class of dehydropenicillins by irradiating substituted 4-acylmethylthio-2-azetidinones and subsequently subjecting the as-obtained product to cyclization. Processing conditions and analytical data are reported.
Drawings
Claims7
A method of preparing dehydropenicillins of the formula ##STR17## wherein X is an aminic group which may be substituted with at least one member selected from the group consisting of aralkyl and acyl and R is a carboxyl group or a salt, an amide, an ester, or thioester thereof comprising:
- (a) irradiating a compound of the formula ##STR18## or of the formula ##STR19## wherein R.sup.1 is selected from the group consisting of alkyl, aryl, and aralkyl and X and R are the same as defined above, in the presence of an inert gas and in an inert anhydrous oxygen-free solvent selected from aromatic solvents and acetonitrile at a temperature of from -10.degree. C. to 40.degree. C.;
- and
- (b) treating said irradiated compound with triethylamine in the presence of a halogen-substituted aliphatic solvent or an aromatic solvent at a temperature of -10.degree. C.+40.degree. C.
A method of preparing dehydropenicillins of the formula ##STR20## wherein X is an aminic group which may be substituted with at least one member selected from the group consisting of aralkyl and acyl and R is a carboxyl group or a salt, an amide, an ester, or thioester thereof comprising:
- (a) irradiating a compound of the formula ##STR21## wherein R.sup.1 is selected from the group consisting of alkyl, aryl, and aralkyl and X and R are the same as defined above, in the presence of an inert gas and in an inert anhydrous oxygen-free solvent selected from aromatic solvents and acetonitrile at a temperature of from -10.degree. C. to 40.degree. C.;
- and
- (b) treating said irradiated compound with a Bronsted or Lewis acid in the presence of an aliphatic or aromatic solvent.
A method of preparing dehydropenicillins of the formula ##STR22## wherein X is an aminic group which may be substituted with at least one member selected from the group consisting of aralkyl and acyl and R is a carboxyl group or a salt, an amide, an ester, or thioester thereof comprising:
- (a) irradiating a compound of the formula ##STR23## wherein R.sup.1 is selected from the group consisting of alkyl, aryl, and aralkyl and X and R are the same as defined above, in the presence of an inert gas and in an inert anhydrous oxygen-free solvent selected from aromatic solvent and acetonitrile at a temperature of from -10.degree. C. to 40.degree. C.;
- and
- (b) heating said irradiated compound to a temperature between about 50.degree. and 150.degree. C. in the presence of an aliphatic or aromatic solvent.
Dependencies are inferred from the claim text.