N. Saitoh

Chemoselective electrolytic chlorination of methyl group of 3-methyl-3-butenoate moiety of thiazoline-azetidinone homologues

Abstract Chemoselective electrochlorination of the methyl group on the 3-methyl-3-butenoate moiety of thiazoline-azetidinone derivatives derived from penicillins G and V has been performed in a CH 2 Cl 2 -H 2 O-NaCl-H 2 SO 4 -(Pt or C electrodes) system by adjusting the amount of electricity passed as well as the concentration of Cl − in the media.

Penicillin-cephalosporin conversion III. A Novel route to 3-chloromethyl-Δ3-cephems

Abstract Synthesis of 3-chloromethyl-Δ 3 -cephems 3 from 4-arenesulfonylthioazetidin-2-ones 1 , derived from penicillins G and V, has been achieved by the electrolytic ene-type chlorination of 1 in a CHC1 3 -aqueous NaCl-H 2 SO 4 -(Pt electrodes) system and subsequent ring closure with NH 3 in DMF.

Penicillin-cephalosporin conversion IV. Direct synthesis of 3'-thiosubstituted cephalosporins from thiazoline-azetidinones

Direct transformation of thiazoline-azetidinones 2, derived from penicillin G and V, into 3′-thio-substituted cephalosporins 4 has been performed by ring opening of the thiazoline moiety with sulfenyl chlorides followed by ring closure with NH3 in dimethylformamide and simultaneous displacement of the allylic chlorine atom with the leaving thiolates.