NEW MATERIAL:A compound of formula I (R is lower alkyl).
EXAMPLE: Methyl threo-2,3-dihydroxy-3-(4-methoxyphenyl)-propionate.
USE: A synthetic intermediate of the compound of formula II which is used as remedy for stenocardia or essential hypertension.
PREPARATION: A compound of formula I is oxidized with, e.g., a permanganate salt to give the compound of formula I readily in high yield and high yield with industrial advantage. The amount of the oxidizing agent is 1W2 times the molar quantity of the compound of formula III. The reaction is carried out at -80W+60°C for 1hr to 20 days. The compound of formula I is subjected to dehydration reaction with 2-nitrothiophenol in a solvent in the presence of a Lewis acid to form a mixture of threo and erythro isomers. Then, the mixture is purified to isolate a compound of formula IV and the compound is subjected to synthetic reactions in order to give the compound of formula II.
ISHIZUKA YORIYASU
FUTSUKAICHI OSAMU
YOSHINO TAISAN
