PROCEDURE FOR THE STEREOSELECTIVE SYNTHESIS OF CYCLINE AMINO ACIDS.

摘要

A process for the preparation of a compound of ** formula ** in which R is C1-C10 alkyl or C3-C10 cycloalkyl, and the pharmaceutically acceptable salts thereof, comprising: a) adding a cyanoacetate of formula (A) , wherein R1 is alkyl or benzyl, to a mixture of a chiral cyclopentanone, a solvent, a carboxylic acid, and a Knoevenagel reaction catalyst, and stirring the mixture in the presence of a water removal medium producing alkene b ) add the product of step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent producing the addition products c) add the products of step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent and stir, and then acidify producing carboxylic acids; and further converting, if desired, to a pharmaceutically acceptable salt by known means.