Water → Capsiate

Participants

Reaction Conditions

Reaction Steps

trans-8-Methyl-6-nonenoic acid (1.00 g, 5.87 mmol), vanillyl alcohol (1.085 g, 7.04 mmol), and Novozym 435 (100 mg) were measured and placed in a flask (25 ml). The mixture in the flask free of a plug was heated with stirring in an oil bath at 50° C. for 16 hours. After 2 to 3 hours of stirring with heating, attachment of water on the wall of the upper part of the flask was observed. The reaction mixture was returned to room temperature, hexane (25 ml) was added, and Novozym 435 and precipitated vanillyl alcohol were removed by filtration. Hexane (25 ml) was added to the filtrate, and the mixture was washed with 5% aqueous citric acid solution (25 ml) and saturated brine (25 ml), and dried over anhydrous magnesium sulfate. Magnesium sulfate was removed by filtration, and the filtrate was concentrated under reduced pressure. Since production of polar impurity other than vanillyl alcohol was confirmed by TLC, the residue was dissolved in 50 ml of hexane and passed through a short column packed with 1.5 g of silica gel, and the silica gel was sufficiently washed away with a mixed solvent of hexane and ethyl acetate (volume ratio 10:1). The above-mentioned impurity was not detected in the eluent by TLC. The eluent was concentrated under reduced pressure to give capsiate (1.56 g, yield 86.6%) as a colorless oil. This capsiate contained a trace amount of trans-8-methyl-6-nonenoic acid.

Provenance & Evidence