Sodium hydride → (S)-2,3,10,10a-tetrahydro-1H,5H-pyrrolo[2,1-c]thieno[2,3-f][1,4]oxazepine-5-one

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Reaction Steps

To a solution of 3-chlorothiophene-2-carboxylic acid (0.5 g; 6.325 mmol) in dimethylformamide (5 ml) was added 1,1′-carbonyldiimidazole (1.07 g; 6.64 mmol) and the solution stirred at room temperature for 1 h, followed by the addition of (S)-(+)-2-pyrrolidinemethanol (0.655 ml; 6.64 mmol). The reaction was stirred at room temperature overnight whereupon 60% sodium hydride in mineral oil (0.507 g; 12.7 mmol) was carefully added and the mixture was heated slowly to 150° C. with the progress of the reaction being monitored by thin layer chromatography. The reaction was cautiously diluted with water and extracted with ethyl acetate and the organic layer washed with water then dried (Na2SO4) and evaporated to give the crude product. Purification by flash chromatography eluting with 0-10% (v/v) methanol in dichloromethane followed by crystalisation from ethyl acetate-petroleum ether (40-60) afforded the title compound (0.15 g). M.p.: 167-167.5° C.; EIMS: m/z=222.2 [M+H]+

Provenance & Evidence