摘要:
An N-chloroimide is prepared by contacting the corresponding imide with molecular chlorine under substantially non-aqueous conditions and in the presence of an epoxy compound and a tertiary amine.
摘要:
N-Chlorophthalimide is prepared by contacting an alkali metal salt of phthalimide with chlorine under substantially non-aqueous conditions in the presence of a halogenated aliphatic hydrocarbon and at a temperature of from about -10.degree. C. to about +40.degree. C.
摘要:
A penicillin sulfoxide ester is reacted with an N-chloro halogenating agent at a temperature of from about 75.degree. C. to about 135.degree. C. and in the presence of an alkylene oxide and calcium oxide to produce a 2-chlorosulfinylazetidin-4-one intermediate. The intermediate, upon separation from the alkylene oxide, calcium oxide, and any conversion products of both the alkylene oxide and calcium oxide, can be treated with stannic chloride to produce a 3-exomethylenecepham sulfoxide.
摘要:
The present invention provides a process for preparing lactone intermediates to 2',2'-difluoronucleosides whereby reversion back to the lactone's open chain precursor is minimized and the desired erythro enantiomer can be selectively isolated from an enantiomeric mixture of erythro and threo lactones in crystalline form. Also provided is a process for producing 2'-deoxy-2',2'-difluoronucleosides in about a 1:1 .alpha./.beta. anomeric ratio, and processes for selectively isolating .beta.-2'-deoxy-2',2'-difluorocytidine, or an organic or inorganic acid addition salt thereof, from the 1:1 .alpha./.beta. mixture.
摘要:
The present invention provides a process for preparing lactone intermediates to 2',2'-difluoronucleosides whereby reversion back to the lactone's open chain precursor is minimized and the desired erythro enantiomer can be selectively isolated from an enantiomeric mixture of erythro and threo lactones in crystalline form. Also provided is a process for producing 2'-deoxy-2',2'-difluoronucleosides in about a 1:1 .alpha./.beta. anomeric ratio, and processes for selectively isolating .beta.-2'-deoxy-2',2'-difluorocytidine, or an organic or inorganic acid addition salt thereof, from the 1:1 .alpha./.beta. mixture.
摘要:
Penicillin sulfoxide esters having the sulfoxide group in the .alpha.-configuration are reacted with an N-chloro halogenating agent at a temperature between about 70.degree. C. and about 120.degree. C. in the presence of an alkylene oxide and preferably also calcium oxide to produce 2-chlorosulfinyl-azetidin-4-one intermediates. The chlorosulfinyl intermediates are then treated with a Friedel-Crafts catalyst, for example, stannic chloride to provide a 3-exomethylenecepham .beta.-sulfoxide. The latter compounds are useful in the preparation of 3-alkoxy and 3-halo substituted cephalosporin antibiotic compounds.
摘要:
A stereoselective glycosylation process for preparing beta-anomer enriched 2'-deoxy-2',2'-difluoropurine and triazole nucleosides and 2'-deoxy-2'-fluoropurine and triazole nucleosides which involves reacting an alpha-anomer enriched 2-deoxy-2,2-difluorocarbohydrate or 2-deoxy-2-fluorocarbohydrate with at least a molar equivalent of a nucleobase derivative in a low freezing inert solvent.
摘要:
A stereoselective glycosylation process for preparing beta- and alpha-anomer enriched 2'-deoxy-2',2'-difluoronucleosides and 2'-deoxy-2'-fluoronucleosides by reacting a concentrated alpha- or beta-anomer enriched 2 -deoxy-2,2-difluorocarbohydrate or 2-deoxy-2 -fluorocarbohydrate with at least a molar equivalent of a nucleobase derivative in a high boiling inert solvent.
摘要:
Ceftazidime pentahydrate in crystalline form is provided in a one-step process comprising acidic removal of protecting groups from an amino-protected and carboxy-protected ceftazidime, separation of aqueous phase after addition of a water-immiscible organic solvent, and precipitation of pentahydrate by adjusting pH of aqueous phase from about 3.5 to about 4.5.