ISSN:
0947-3440
Keywords:
Benzyl 2,3-dioxobutyrate
;
2-Iso-oxacephems
;
Antibacterial activity
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
General methods have been developed for the synthesis of 7-amino-2-iso-oxacephem-4-carboxylic acid esters 21a,b; 35b. Clayfen [Fe(III) nitrate supported by montmorillonite] was used for the preparation of benzyl 2,3-dioxobutyrate (3). The latter readily reacted with N(1)-unsubstituted β-lactams (9a, 28) to give products formed by addition reaction on the middle carbonyl-C atom. These intermediates furnished the corresponding acetoacetic esters 10, 29 which gave by ring closure the O-mono- and the O,N-diprotected-2-iso-oxacephems (11, 30). Intermolecular carbene insertion was used for the synthesis of tert-butyl 2-(2-oxoazetidin-1-yl)acetoacetates 19a,b whose ring closure led to the tert-butyl 2-iso-oxa-cephem-4-carboxylates 20a,b. The O-protecting tert-butyl group could be removed without decomposition of the 2-isooxacephem moiety to give 2-iso-oxacephem-4-carboxylic acids 2a,b which exhibit antibacterial activity against Grampositive microorganisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.1995199505120
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