Patent ID: 6969778

Claim:
A process for the preparation of neolignan 3-ethyl-2-methyl-3-(2â€³,4â€³,5â€³-trirnethoxy) phenyl-1-(2â€²,4â€²,5â€²-trimethoxy) phenyl-1-propene from toxic Î²-asarone or Î²-asarone rich Acorus calamus oil containing Î± and Î³-asarone, the said process comprising the following steps: a) hydrogenating Î²-asarone or Î²-asarone rich calamus oil containing Î± and Î³-asarone in presence of methanol or ethanol, 10% Pd/C catalyst, with or without ammonium formate under pressure between 0-40 psi at room temperature, 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- 2 and washing the filtrate twice with acetic acid, 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-(2â€³,4â€³,5â€³-trimethoxy) phenyl-1-(2â€²,4â€²,5â€²-trimethoxy)phenyl-1-propene.