O-Xylene → 3-Hydroxy-2-(4-methoxyphenyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one, (2S,3S)-

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 40 g of methyl (2R,3S)-2,3-epoxy-3-(4-methoxyphenyl)propionate, 26.5 g of 2-aminothiophenol and 300 ml of xylene is heated at 110° to 120° C. for 1 hour, whereby the reaction mixture containing methyl (2S,3S)-3-[(2-aminophenyl)thiol]-2-hydroxy-3-(4-methoxylphenyl)propionate is obtained. 380 mg of methanesulfonic acid are added to the mixture and the mixture is refluxed for 7 hours. During the reaction, methanol formed is removed by the azeotropic distillation with xylene. The mixture is cooled to under 10° C. and then stirred for 1 hour. Precipitated crystals are collected by filtration, washed with cooled methanol and then dried, whereby 49.1 g of (2S,3S)-3-hydroxy-2-(4-methoxyphenyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one are obtained. Yield: 84.8% m.p.: 204°-205° C. [α]D20 +115° (c=0.5, dimethylformamide)

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