Ring-opening process for preparation of 2-chlorosulfinyl azetidinones
US5070195A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1990 |
| Grant date | Dec 3, 1991 |
| Priority date | — |
| Expiry date | Mar 7, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D205/095
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
An improved method for preparing 2-chlorosulfinyl azetidine-4-one comprises heating a penicillin sulfoxide ester with an N-chlorohalogenating agent at a temperature of about 75.degree. C. to about 140.degree. in an inert organic solvent, and in the presence of an organic solvent insoluble, strongly basic ion exchange resin. Desirably, the ion exchange resin comprises a styrene-divinyl benzane copolymer which is about 2 to 16% cross-linked and incorporates a quaternary ammonium functionality. Such ion exchange resins are commercially available. The 2-chlorosulfinyl azetidine-4-one which is produced by this method can be cyclized in the presence of a Friedel-Crafts catalysts to afford the 3-exomethylene cepham sulfoxide ester in yields of 80-90%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.