Process for the preparation of (S) and (R) 2-substituted- 4-phenylbutyric acids, their salts and derivatives

摘要

The invention describes a process for the preparation of compounds of formula I <IMAGE> where "R" represents hydrogen, methyl, ethyl, t-butyl, benzyl or trimethylsilyl and R1 hydrogen, trimethylsilyl, acyl or trifluoromethanesulphonyl, resulting from resolution of (R, S)-2-hydroxy-4-phenylbutyric acid with the bases D(-)threo or L(+)threo 1,penitrophenyl-2-amino- 1,3-propandiol, from which (R) or (S) 2-hydroxy-4- phenylbutyric acids are isolated, esterified and their 2- trimethylsilyloxy derivatives are caused to react with triflic anhydride. The (S)-hydroxy acid -> (R)-hydroxy acid conversion takes place through reaction of the triflates with triethylamine acetate with region- selective inversion and hydrolysis of the acetate with retention of configuration. Compounds having application in medicine in the field of anti-hypertensives, and in agriculture as growth regulators and insect repellents.