Patent ID: 7803955

Claim:
A method for preparing a precursor of α-CEHC, 2,5,7.8-tetramethyl-2-(2′-carboxyethyl) -6-acetoxychroman, which comprises the following steps: a) carrying out an acid-catalyzed reaction of condensation of trimethyl hydroquinone with linalool in boiling n-octane; b) treating the product obtained in step a) in said condensation reaction with acetic anhydride in pyridine; c) ozonizing the product from step b) in the presence of Ba(OH) 2 in acetone at room temperature; d) oxidizing the product from step c) in the same solvent with Jones' reagent (CrO 3 /H 2 SO 4 ); e) isolating the target product by column chromatography.