156662-53-2

Upstream product

• 100-11-8 1-bromomethyl-4-nitro-benzene 
• 156767-52-1 (3S,4R)-1-<(R)-1-<<(p-nitrobenzyl)oxy>carbonyl>-(S)-2-hydroxypropyl>-3-(4-nitrophthalimido)-4-styrylazetidin-2-one 
• 156662-49-6 (2R,3S)-3-Hydroxy-2-[(2S,3S)-2-methanesulfonyloxymethyl-3-(5-nitro-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-4-oxo-azetidin-1-yl]-butyric acid 4-nitro-benzyl ester 
• 156662-51-0 (Z)-3-Hydroxy-2-[(2S,3S)-2-methanesulfonyloxymethyl-3-(5-nitro-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-4-oxo-azetidin-1-yl]-but-2-enoic acid 4-nitro-benzyl ester 
• 133622-35-2 (2R,3S)-3-Hydroxy-2-[(2S,3S)-2-hydroxymethyl-3-(5-nitro-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-4-oxo-azetidin-1-yl]-butyric acid 4-nitro-benzyl ester 
• 1026269-90-8 (2R,3S)-2-[(2S,3S)-2-Formyl-3-(5-nitro-1,3-dioxo-1,3-dihydro-isoindol-2-yl)-4-oxo-azetidin-1-yl]-3-hydroxy-butyric acid 4-nitro-benzyl ester 
• 18686-82-3 2-mercapto-1,3,4-thiadiazole 
• 156662-52-1 p-nitrobenzyl (6S,7S)-3-bromomethyl-7-(4-nitrophthalimido)-8-oxo-1-aza-4-oxabicyclo<4.2.0>oct-2-ene-2-carboxylate 

Relevant academic research and scientific papers

A convenient one pot asymmetric synthesis of cis-β-lactams: Key precursors for optically active 2-oxaisocephems

Asymmetric annelation of the disilylated imine 3 generated in situ from D-threonine 2 with acid chlorides 4 and triethylamine followed by esterification provided cis-β-lactams 5 and 6 in excellent yields with high diastereoselectivity under mild condition