62014-72-6

Upstream product

• 62284-23-5 (R)-2-[(2R)-2r-benzooxazol-2-yldisulfanyl-4-oxo-3c-(2-phenyl-acetylamino)-azetidin-1-yl]-3-methyl-but-3-enoic acid methyl ester 
• 62284-24-6 methyl (2R)-<(3S,4R)-4-(benzothiazol-2-yldithio)-2-oxo-3-phenylacetamidoazetidin-1-yl>-3-methylbut-3-enoate 
• 24652-72-0 methyl 6β-(phenylacetamido)penicillanate 1β-oxide 
• 83290-70-4 2-(7-oxo-2,6-diaza-4-thiabicyclo<3.2.0>hept-2-en-6-yl)-3-chloromethyl-3-butenoate 

Relevant academic research and scientific papers

Penicillin-cephalosporin conversion. VII. An improved synthesis of 3-methylenecephams

Efficient conversion of 2-(7-oxo-2,6-diaza-4-thiabicyclo left bracket 3. 2. 0 right bracket hept-2-en-6-yl)-3-chloromethyl-3-butenoates (4), derived from natural pencillins, into 3-methylenecephams (1) has been performed by a simple two-step operation, which comprises replacement of the allylic chlorine atom of 4 with iodine and subsequent acid-catalyzed hydrolysis, leading to 1 in 70-54% overall yields. In the latter step, the ring opening of the thiazoline moiety and the intramolecular substitution of the iodide with the thiol group proceed simultaneously.