Phosphoric Acid → Retinoic Acid

Participants

Reaction Conditions

Reaction Steps

A 200-ml three-necked flask was charged under an atmosphere of nitrogen with 8.86 g of vitamin A aldehyde (80.1% purity, 25 mmoles, ratio of 13-cis form: 92%), 50 g of 2-methyl-2-butene, 20 ml of dioxane and 10 g of a 25% aqueous sodium chlorite solution, and the mixture was mechanically stirred vigorously. Then, 32 g of an aqueous phosphoric acid solution was added dropwise thereto, while the internal temperature was maintained at 5° C., over 15 minutes. Vigorous stirring was continued at 5° C. for further 40 minutes. Confirmation of completion of the reaction and after-treatment were conducted in the same manner as in Example 1, to obtain 3.46 g of vitamin A acid with a purity of at least 99%. The yield was 46%. The vitamin A acid thus obtained had a 13-cis form ratio of 95%.

Provenance & Evidence