| abstract |
(57) [Summary] [Objective] To produce a hydroxyflavan compound industrially advantageously. [Structure] The compound of formula (I) is obtained by condensation reaction of polyhydric phenol and ketone. (In the formula, R 1 to R 5 represent alkyl, cycloalkyl, aralkyl or aryl, but R 2 and R 3 may be hydrogen, and R 1 and R 2 and R 4 and R 5 are bonded to each other. A cycloalkane ring may be formed, and W, X, Y And at least one of Z represents a hydroxyl group, and the rest represent hydrogen, halogen, alkyl, alkenyl, cycloalkyl, aralkyl, arylalkenyl or aryl), in the presence of an acid catalyst, water. The condensation reaction is carried out in the presence of water or seed crystals in an organic solvent immiscible with. [Effect] While keeping the reaction rate of polyhydric phenol high, A hydroxyflavan compound can be produced in high yield and with high selectivity. |