Patent ID: 6989467
Filing Date: 2006-01-24
Classification: C07C

Abstract:
1. A microwave assisted single pot process for the preparation of 4-vinyiphenol or its derivatives of general formula (I) wherein R 1 =OH or OCH 3 , R 4 =—CH—CH 2 and rest R 2 , R 3 , R 5 and R 6 =H, OH or OCH 3 or combinations thereof, the said process comprising steps of: a. reacting 4-hydroxyphenylaldehydes or its derivatives with malonic acid in presence of an organic base and an organic acid under microwave irradiation for a period ranging between 1 and 20 minutes, b. cooling the mixture, pouring the cooled mixture into ice-cold water, extracting with an organic solvent, separating the organic layer, c. washing the organic layer of step (b) with dilute hydrochloric acid, followed by saturated sodium chloride solution, drying the washed organic layer over anhydrous sodium sulphate, filtering and evaporating the organic layer under reduced pressure to obtain a liquid residue, d. purifying the liquid residue of step (c) over silica gel column, eluting with a mixture of hexane ethyl acetate, and e. obtaining the required 4-hydroxyvinylphenols or its derivative of formula (1).