VERBENONE PREPARATION METHOD Russian patent published in 2005 - IPC

FIELD: industrial organic synthesis.

SUBSTANCE: invention provides a method for preparation of verbenone, which is important intermediate in synthesis of perfumes, optically active insect pheramonesm and therapeutical preparations. Method involves catalytic oxidation of α-pinene with air oxygen, wherein catalysts are selected from group including bivalent Cu, Zn, Pb, Co, Mn, and Ni (preferably Co, Mn, Ni), and Cr(III), or pyridine complex having formula (i) M(C₅H₅N)₂X₂, in which M represents bivalent transition metal selected from group including, in particular, Co, Ni, and Mn; and X represents halogen such as Cl or Br; or (ii) CrO₃·M(C₅H₅N)₂. Resulting hydroperoxides are then decomposed via fractioning steam distillation in alkali medium, wherein nonconverted α-pinene is separated at temperature below 97°C, whereas oxidized product fraction is distilled at 97-100°C and then subjected to additional oxidation with chromic mixture followed by recovering verbenone from additionally oxidized products. Verbenone is further freed from myrtenal ingredient by reducing it into myrtenol with alkali metal borohydride in alcohol or water-alcohol solution, after which verbenone is recovered from reduction products.

EFFECT: increased (by 22-30%) yield of verbenone from oxidized α-pinene.

5 cl, 1 tbl