128791-76-4

Upstream product

• 192517-62-7 [(2S,3S)-2-(tert-Butyl-dimethyl-silanyloxymethyl)-4-oxo-3-phenylacetylamino-azetidin-1-yl]-acetic acid 4-nitro-benzyl ester 
• 128791-75-3 p-nitrobenzyl (2S,3S)-3-azido-2-(tert-butyldimethylsiloxymethyl)-4-oxoazetidine-1-acetate 
• 104227-75-0 (3S,4S)-3-azido-4-hydroxymethyl-1-(p-nitrobenzylcarbamoylmethyl)azetidin-2-one 

Downstream Products

• 128791-77-5 p-nitrobenzyl (2S,3S)-2-(imidazol-1-yl)carbonyloxymethyl-4-oxo-3-(phenylacetamido)azetidine-1-acetate 

Relevant academic research and scientific papers

Enantioselective synthesis of 2-isocephem and 2-isooxacephem antibiotics

The azido lactone 8 was prepared in a highly stereoselective manner by introduction of an azide function to the lactone 6 derived from L-aspartic acid, and then was converted into (2S,3S)-3-amino-2-azido-4-hydroxybutanoic acid 4. Four-component condensation of the amino acid 4, p-nitrobenzyl isocyanide and formaldehyde or 2,2-diethoxyacetaldehyde furnished the corresponding 3,4-cis-azetidinone 16 or 26 in excellent yield. 3-Methoxy-2-isooxacephalosporin was prepared by the intramolecular acylation of imidazolide 23 derived from compound 16. 3-Unsubstituted 2-isocephem and 2-isooxacephem analogues were prepared from the azetidinone 26.

Synthesis of 3-Methoxy-2-iso-oxacephalosporin

Optically active 3-methoxy-2-iso-oxacephalosporins are efficiently prepared via intramolecular acylation as a key step.