Patent ID: 6969778
Filing Date: 2005-11-29
Classification: C07C

Abstract:
1. A process for the preparation of neolignan 3-ethyl-2-methyl-3-(2″,4″,5″-trirnethoxy) phenyl-1-(2′,4′,5′-trimethoxy) phenyl-1-propene from toxic β-asarone or β-asarone rich Acorus calamus oil containing α and γ-asarone, the said process comprising the following steps: a) hydrogenating β-asarone or β-asarone rich b) purifying the product of step (a) over silica gel column to obtain 2,4,5-trimethoxyphenylpropane of formula (I), c) stirring the compound of formula (I) of step (b) with DDQ in presence of organic solvent selected from group of acetic acid or propionic acid at room temperature for overnight, d) filtering the precipitate solid of DDQH- e) evaporating the filtrate of step (d), to obtain a concentrated mixture, f) extracting the mixture of (e) with dichloromethane wherein the mixture of acetic acid and dichloromethane forms an organic layer, g) washing the organic layer of step (f) with brine followed by 10% sodium bicarbonate and another second washing with brine, h) drying the organic layer obtained in step (g) over anhydrous sodium sulphate, wherein a residue is formed, i) chromatographing the residue of step (h) over silica gel using hexane-ethyl acetate mixture to obtain three sets of fractions, and j) crystallizing fractions of step (i) using mixture of hexane and methanol, and k) obtaining crystallized fractions of 2,4,5-trimethoxyphenylpropane of formula I, 1-(2,4,5-trimethoxy) phenyl-1-propanone and 2,4, neolignan 3-ethyl-2-methyl-3-(2″,4″,5″-trimethoxy) phenyl-1-(2′,4′,5′-trimethoxy)phenyl-1-propene.