| 摘要 |
Manufacture of polyene compounds which can utilize the mother liquors from the commercial synthesis of vitamin A, including oxenin and hydroxenin mother liquors. Method of utilising materials previously regarded as waste. A cis-beta-carotene is prepared by (a) reacting a cis-vitamin A isomeric mixture with a compound selected from a group consisting of (1) MnO2, (2) KMnO4, and (3) K2Cr2O7 to form a cis-vitamin A aldehyde isomeric mixture, and (b) reacting the so-formed cis-vitamin A aldehyde isomeric mixture with a compound selected from the group consisting of (1) a triaryl phosphine salt of a vitamin A alcohol, (2) a triarylmonoalkyl phosphine salt of a vitamin A alcohol and (3) a monoaryl-dialkylphosphine salt of a vitamin A alcohol in contact with a proton acceptor (e.g. alkali metal- or alkaline earth metal-hydroxide, amide, or alcoholate, a Group I metallo alkyl or a Group I metallo aryl or an alkyl or aryl magnesium halide), to form the cis-beta-carotene. The cis-beta-carotene may then be heated at 90-95 deg.C in heptane to form trans-beta-carotene. |
