Propionyl chloride → (-)-cis-2-(4-methoxyphenyl)-3-propionyloxy-5-[2-(N-benzyloxycarbonyl-N-methylamino)ethyl]-8-chloro-2,3-dihydro-1,5-benzothiazepin-4(5H)-one

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Reaction Steps

490 mg of propionyl chloride are added under ice-cooling to a solution of 2.15 g of (-)-cis-2-(4-methoxyphenyl)-3-hydroxy-5-[2-(N-benzyloxycarbonyl-N-methylamino)ethyl]-8-chloro-2,3-dihydro-1,5-benzothiazepin-4(5H)-one in 20 ml of pyridine, and the mixture is stirred at room temperature for 3 hours. Then, the mixture is evaporated under reduced pressure. The residue is several times evaporated together with benzene, and ice-water is added to said residue. The aqueous mixture is extracted with ethyl acetate, and the extract is washed with water, 10% hydrochloric acid, water, an aqueous saturated sodium bicarbonate solution and water, successively. Said extract is dried and evaporated under reduced pressure to remove solvent. 2.19 g of (-)-cis-2-(4-methoxyphenyl)-3-propionyloxy-5-[2-(N-benzyloxycarbonyl-N-methylamino)ethyl]-8-chloro-2,3-dihydro-1,5-benzothiazepin-4(5H)-one are obtained as caramel.

Provenance & Evidence