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Report | Regular issue | Vol 12, No. 6, 1979, pp.795-800
Published online, 1st January, 1970
DOI: 10.3987/R-1979-06-0795
Synthetic Studies on β-Lactam Antibiotics. V. Stereoselective Synthesis of 1,9b-Dihydro-2H,4H-2-oxo-azeto[1,2-c][1,3]benzoxazine-4-carboxylic Acid Derivatives

Tetsuji Kametani,* Kazuo Kigasawa, Mineharu Hiiragi, Kikuo Wakisaka, Hideo Sugi, and Keizo Tanigawa

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan


2,2,2-Trichloroethyl 1-phthalimido-1,9b-dihydro-2H,4H-2-oxo-azeto[1,2-c][1,3]benzoxazine-4-carboxylate (11) was synthesised stereoselectively by cyclisation of 2,2,2-trichloroethyl 2-[cis-4-(2-hydroxyphenyl)-3-phthalimido-2-oxo-1-azetidinyl]2-hydroxyacetate (8), which was prepared from N-(2-benzyloxybenzylidene)-2,4-dimethoxybenzylamine (4) by cycloaddition with ketene, followed by debenzylation and condensation with 2,2,2-trichloroethyl glyoxalate. The corresponding p-nitrobenzyl ester (12) which was obtained by a similar method, was converted to the free carboxylic acid (16).