Ethyl Acetate → t-Butyl alpha-[3(S*)-azido-2-oxo-6(R*)-phenylperhydroazepin-1-yl]acetate

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Reaction Steps

0.9 ml of t-butyl bromoacetate followed by 219 mg of sodium hydride (as a 55% w/w dispersion in mineral oil) were added, under a stream of nitrogen, to a solution of 1.05 g of 3(S*)-azido-6(R*)-phenylperhydroazepin-2-one (Isomer A) [prepared as described in Example 1(f)] in 10 ml of dimethylformamide, whilst ice-cooling. The mixture was stirred for 1.5 hours, and then ethyl acetate and water were added. The ethyl acetate layer was separated, washed with water, and dried over anhydrous magnesium sulfate. The solvent was then distilled off. The residue was purified by silica gel column chromatography using a 1:4 by volume mixture of ethyl acetate and cyclohexane as eluent, to give 1.54 g of the title compound as crystals, melting at 119°-121° C.

Provenance & Evidence