Synthetic dihydrocapsiate is a viscous colorless to yellowish oil that contains more than 94 percent dihydrocapsiate. Dihydrocapsiate, ((4-hydroxy-3-methoxybenzyl) 8-methylnonanoate), has the molecular formula C18H28O4, and a molecular weight of 308.41, with the Chemical Abstracts Service Registry Number 205687-03-2.
Ajinomoto, the manufacturer, indicates that the method of manufacture of synthetic dihydrocapsiate involves the esterification of vanillyl alcohol (V-OH) and 8-methylnonanoic acid (MNA) catalyzed by an immobilized lipase preparation. The esterification is followed by filtration, extraction with n-hexane, and evaporation. Ajinomoto also describes the manufacturing process for the starting materials V-OH and MNA. MNA is prepared from isobutyl bromide and 6-bromohexanoic acid ethyl ester through a Grignard coupling reaction and deprotection process to give a carboxylic acid. V-OH is prepared from vanillin by reduction, followed by evaporation of the solvent (tetrahydrofuran).
Specifications include limits on lead (less than 1 mg/kg), arsenic (less than 1 mg/kg), cadmium (less than 1 mg/kg), V-OH (less than 1 percent), other reaction byproducts (less than 2 percent), and residual solvents, n-hexane and tetrahydrofuran (less than 5 mg/kg).