Hydrochloric Acid → p-Nitrobenzyl alpha-[4-cyclopropylmethoxycarbonylthio-3-phenoxyacetamido-2-oxoazetidin-1-yl]-alpha-(2-bromo-1-hydroxyethylidene)acetate

To a solution of p-nitrobenzyl α-[4-cyclopropylmethoxycarbonylthio-3-phenoxyacetamido-2-oxoazetidine-1-yl]-α-[2-bromo-1-(morpholin-4-yl)ethylidene]acetate (300 mg) in a mixture of methanol (22 ml) and methylene chloride (3.5 ml), and the mixture is stirred at room temperature under nitrogen atmosphere after addition of 10% hydrochloric acid (4 ml). After 2 hours, the reaction mixture is poured into ice water, and is extracted with chloroform. The extract solution is washed with water, dried, and evaporated to give p-nitrobenzyl 4-cyclopropylmethoxycarbonylthio-3-phenoxyacetamido-2-oxo-α-(2-bromo-1-hydroxyethylidene)azetidine-1-acetate (252 mg). Foam. Yield: 92.8%. IR: νmaxCHCl 3426, 1781, 1710, 1690, 1601 cm-1. NMR: δCDCl3 0.23-1.33m5H, 3.84-4.36m4H, 4.55s2H, 5.10-5.23m3H, 5.88d(5 Hz)1H, 6.83-8.33m9H, 12.0s1H.