341554-36-7

Upstream product

• 341554-37-8 (αR,3R)-3-(1-acetoxyethyl)-2-methoxycarbonyl-1-(4-methoxyphenyl)-4-oxoazetidin-2-carboxylic acid 
• 341554-31-2 dimethyl {N-[(2S,3R)-3-acetoxy-2-bromobutyryl]-N-(4-methoxyphenyl)aminomalonate} 
• 341554-32-3 dimethyl [(αR,3R)-3-(1-acetoxyethyl)-1-(4-methoxyphenyl)-4-oxoazetidin-2,2-dicarboxylate] 
• 112245-37-1 (2S,3R)-2-bromo-3-acetoxybutyroyl chloride 
• 171340-06-0 (2S,3R)-2-bromo-3-(ethanoyloxy)butanoic acid 
• 927678-39-5 dibenzyl {[(2S,3R)-3-acetoxy-2-bromobutyryl](4-methoxyphenyl)amino}malonate 
• 927678-41-9 (3R)-3-[(1R)-1-acetoxyethyl]-2-(benzyloxycarbonyl)-1-(4-methoxyphenyl)-4-oxoazetidine-2-carboxylic acid 
• 927678-38-4 dibenzyl [(4-methoxyphenyl)amino]malonate 
• 927678-43-1 benzyl (2R,3R)-3-[(1R)-1-acetoxyethyl]-1-(4-methoxyphenyl)-4-oxoazetidine-2-carboxylate 
• 341554-33-4 methyl [(αR,2RS,3R)-3-(1-acetoxyethyl)-1-(4-methoxyphenyl)-4-oxoazetidin-2-carboxylate] 

Downstream Products

• 733769-91-0 (αR,3R,4R)-3-(1-acetoxyethyl)-4-(mesyloxymethyl)-N-(4-methoxyphenyl)-azetidin-2-one 
• 733769-93-2 (Z)-2-[(2R,3R)-3-((R)-1-Acetoxy-ethyl)-2-methanesulfonyloxymethyl-4-oxo-azetidin-1-yl]-3-hydroxy-but-2-enoic acid benzyl ester 
• 733769-94-3 benzyl (αR,6R,7R)-7-(1-acetoxyethyl)-3-methyl-2-isoxacephem-4-carboxylate 

Relevant academic research and scientific papers

Synthesis of thienamycin-like 2-iso-oxacephems with optional stereochemistry

All four trans-stereoisomers of 7-(1-hydroxyethyl)-2-iso-oxacephem-4-carboxylic acids, which are the 2-iso-oxacephem analogues of Thienamycin, have been synthesized. (αR,6R,7R)- and (αS,6S,7S)-7-(1-hydroxyethyl)-3-methyl-2-iso-oxacephem-4-carboxylic acids have been prepared starting from l- and d-threonine, the configuration at the α-position was inverted by using Mitsunobu reactions providing the (αS,6R,7R)- and (αR,6S,7S)-diastereomers of the compounds above. A synthetic route to the cis-annelated analogues was also worked out.

Synthesis of pure methyl [(2S,3R,αR)-1-(3-bromo-4-methoxyphenyl)-3-(α-acetoxy)ethyl-4- oxoazetidin-2-carboxylate] and its enantiomer

Synthesis of key intermediates leading to 2-iso-oxacephems was carried out starting from L- and D-threonine. As predicted in our previous paper (Tetrahedron Lett. 1995, 36, 8303-8306) all diastereomers of 2-iso-oxacephems can be prepared from the appropriate enantiomers of the amino acid threonine. The absolute configuration of the 2,3- and α-carbon atoms in the β-lactam structure was determined by X-ray crystallographic studies.

Stereocontrolled synthesis of methyl αR,2S,3R-3-(1-acetoxyethyl)-1-(4-methoxyphenyl)-4-oxoazetidine-2- carboxylate

A stereocontrolled synthesis of the key intermediates for 2-iso-oxa- and 2-isocephems is described. The absolute configuration of the title ester 8a is unambiguously determined by using X-ray analysis.