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1,3‐Dipolar cycloaddition reactions of vinylcephalosporins with diazoalkanes
Author(s) -
Pitlik János,
Gunda Tamás E.,
Miskolczi István
Publication year - 1990
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570270521
Subject(s) - chemistry , diazomethane , cycloaddition , adduct , stereoselectivity , 1,3 dipolar cycloaddition , stereochemistry , computational chemistry , medicinal chemistry , organic chemistry , catalysis
The vinylcephalosporin ( 1 ) undergoes a regio‐ and stereoselective 1, 3 ‐dipolar cycloaddition with diazomethane to give novel cephalosporins, a 3 ‐pyrazolinocephem ( 4 ) and a double adduct ( 5 ). The vinylcephalosporin sulphoxide ( 2 ) gives only the pyrazolinocephem ( 7 ). In the reaction with diphenyldiazomethane upon heating the initially formed pyrazolines decompose and cyclopropylcephalosporin ( 9 ) formation takes place. The determination of the structures and stereochemistry of these compounds is also described.