Ethanol → N-[[2'-(1-Triphenylmethyltetrazol-5-yl)biphenyl-4-yl]methyl]valine methyl ester

関与物質

反応手順

N-[[2′-(1-Triphenylmethyltetrazol-5-yl)biphenyl-4-yl]methyl]valine methyl ester (X) is prepared according to the process described in U.S. Pat. No. 5,399,578. N-[[2′-(1-triphenylmethyltetrazol-5-yl)biphenyl-4-yl]methyl]valine methyl ester (X) is reacted with a molar equivalent of oxalic acid or its hydrates selected from oxalic acid dihydrate in an organic solvent selected from alcohols such as ethanol, n-propanol, isopropanol, n-butanol, isobutanol, methylene chloride, ethyl acetate or mixtures thereof, at a temperature of about −20° C. to about 70° C. and the product obtained is isolated by filtration and dried. The product obtained is purified in a solvent selected from chlorinated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane, preferably methylene chloride to produce N-[[2′-(1-triphenylmethyltetrazol-5-yl)biphenyl-4-yl]methyl]valine methyl ester oxalate (Xa) in crystalline form. It has been observed that preparation of oxalic acid salt of Formula (X) results in greater than 98% purity of product by HPLC analysis.

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