Oxalic Acid → (+)-cis-2-(4-methoxyphenyl)-3-(4-chloro-3-nitrobenzoyloxy)-5-[2-(N-methyl-N-ethylamino)ethyl]-2,3-dihydro-1,5-benzothiazepin-4(5H)-one oxalate

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Reaction Steps

0.5 ml of triethylamine is added to a solution of 430 mg of (+)-cis-2-(4-methoxyphenyl)-3-hydroxy-5-[2-(-N-methyl-N-ethylamino)ethyl]-2,3-dihydro-1,5-benzothiazepin-4(5H)-one hydrochloride in 10 ml of methylene chloride, and 270 mg of 4-chloro-3-nitrobenzoyl chloride are added thereto under ice-cooling and stirring. The mixture is stirred at room temperature overnight. The mixture is washed with water, dried and then condensed under reduced pressure to dryness. The residue is dissolved in acetone, and 90 mg of oxalic acid are added thereto. The mixture is allowed to stand. Crystalline precipitates are collected by filtration and dried. 410 mg of (+)-cis-2-(4-methoxyphenyl)-3-(4-chloro-3-nitrobenzoyloxy)-5-[2-(N-methyl-N-ethylamino)ethyl]-2,3-dihydro-1,5-benzothiazepin-4(5H)-one oxalate are obtained as colorless needles. Yield: 61%.

Provenance & Evidence