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Die Umwandlung von Penicillinen in Cephalosporine. Modifikationen von Antibiotika, 3. Mitteilung
Author(s) -
Heusler K.
Publication year - 1972
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19720550209
Subject(s) - chemistry , thiazolidine , lactam , penicillin , stereochemistry , thio , ring (chemistry) , organic chemistry , antibiotics , biochemistry
A new method for the degradation of the thiazolidine ring in penicillins is described. Penicillin V ( 8a ), penicillin G ( 8b ) and 6‐ t ‐butoxycarbonylaminopenicillanic acid ( 33 ) (BOC‐6‐APA) were converted via their acylazides and isocyanates ( 10 and 34 ) into 2,2,2‐trichloroethyl urethanes ( 11 and 35 ). Reductive removal of the trichloroethoxycarbonyl groups in an aqueous medium gave the 3‐hydroxy‐penam‐derivatives 13 and 36 . The structure and various reactions of these carbinolamides are discussed in detail. An oxidative radical fragmentation (using lead tetraacylates and light) followed by thermal treatment transformed the 3‐hydroxy‐penam‐derivatives into the N‐formyl‐β‐lactam‐thio‐enolethers 27 and 37 in which the formyl group could be replaced by hydrogen. Reactions of the β‐lactam and thio‐enolether functions are described. The BOC‐derivative 37 can be transformed into the isomeric compound 3 , an intermediate in Woodward's total synthesis of cephalosporins.