PURPOSE: To obtain a compound useful as a synthetic intermediate for diltiazem hydrochloride which is a remedy for angina pectoris and essential hypertension in high purity and yield, by reacting a 4-methoxyphenyl-propionic acid ester derivative with 2-nitrothiophenol.
CONSTITUTION: A novel threo-2,3-dihydroxy-3-(4-methoxyphenyl)-propionic acid ester derivative expressed by formula I (R is lower alkyl) and 2-nitrothiophenol expressed by formula II are subjected to dehydration reaction in the presence of a Lewis acid, e.g. bron trifluoride, in a solvent, e.g. methylene chloride, etc., at -20W+100°C, preferably 0W80°C for 1W6hr to afford the aimed substance expressed by formula III. The novel starting compound expressed by formula I is obtained by reacting a readily available trans-4-methoxycinnamic acid ester expressed by formula IV with an oxidizing agent.
ISHIZUKA YORIYASU
FUTSUKAICHI OSAMU
YOSHINO TAISAN
Next Patent: PRODUCTION OF THREO-2-HYDROXY-3-(4-METHOXYPHENYL)-3-(2-NITROPHENYLTHIO)-PROPIONIC ACID