| 摘要 |
1286216 Polyene compounds F HOFFMANN LA ROCHE & CO AG 22 Dec 1970 [31 Dec 1969] 60838/70 Heading C2V Polyene compounds of formula in which R represents a 2,6,6-trimethyl-cyclohex- 1-en-l-yl residue, a 2,6,6-trimethyl-cyclohex-2- en-l-yl residue, a 2,6,6-trimethyl-cyclohexa-1,3- dien-1-yl residue, a 2,6-dimethyl-hepta-1,5- dien-1-yl residue, a 2,6-dimethyl-hepta-l,3,5- trien-1-yl residue or a 2-methyl-4-[2,6,6-trimethyl-cyclohex-1-en-1-yl]-buta-1,3-dien-1-yl residue and X represents a hydrogen atom or an alkali metal, are obtained by oxidizing a compound of formula where Y is a hydroxy, alkanoyloxy or aroyloxy group, with silver (I) oxide and an alkali metal hydroxide or an alkali metal alkanolate optionally in water and/or a water-miscible organic solvent. Alkali metal salts of Formula I may be converted to the free acid by reaction with a mineral acid e.g. phosphoric acid. The silver (I) oxide may be formed in situ. In examples alltrans-vitamin A acetate is converted to all-transvitamin A acid, 13-cis-vitamin A acetate is converted to 13-cis-vitamin A acid, γ-vitamin A acetate is converted to γ-vitamin A acid, vitamin A 2 alcohol is converted to vitamin A 2 acid, vitamin A is converted to vitamin A acid and vitamin A-3,5-dinitro-benzoate is converted to vitamin A acid. |
