Benzoic acid, 2-mercapto-, methyl ester → 2,3,4,5-Tetrahydro-1,4-benzothiazepin-5-one

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Reaction Steps

To a cooled solution of methyl 2-sulfanylbenzoate (200 g, 1.19 mol) in tetrahydrofuran and N,N-dimethylformamide (2 L, V/V=1/1) was added 2-chloroethanamine hydrochloride (138 g, 1.19 mol) at 0° C. followed by sodium hydride (143 g, 3.57 mol, 60% in mineral oil) in portions. After being stirred at room temperature overnight, the reaction mixture was poured into ice-water and extracted with ethyl acetate (900 mL×4). The organic layers were combined, washed with brine (900 mL×3), dried over sodium sulfate and concentrated in vacuo. The residue was stirred in a mixture solution of ethyl acetate and petroleum ether (300 mL, V/V=1/1) for 1 hour. The solid was collected by filtration and dried in vacuo to afford 100 g of 3,4-dihydro-1,4-benzothiazepin-5(2H)-one (yield was 47%).

Provenance & Evidence