| 摘要 |
3-Methylenecepham 1-sulphoxides of the formula <IMAGE> in which the substituents are defined in Claim 1 are prepared. These compounds are prepared by bringing about ring closure in a corresponding sulphinylazetidinone of the formula <IMAGE> in which X is chlorine or bromine, an alcohol or thioalcohol residue, an ester or a thioester residue, or an amino radical. If X is chlorine or bromine, the compound II is reacted with a Friedel-Crafts catalyst of the Lewis acid type, with a Friedel-Crafts catalyst of the Bronsted protonic acid type or with a metathetical cation former in a dry inert organic solvent, or is dissolved in an organic Bronsted acid. If X in compounds II is an alcohol, thioalcohol, ester or thioester residue or an amino radical, reaction is carried out with a Friedel-Crafts catalyst of the Bronsted protonic acid type in a dry inert organic solvent, or the compound is dissolved in an organic Bronsted acid. The resulting compounds can be used for the preparation of cephem antibiotics. |
