| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new methoxyalcohol derivative which is useful as a raw material for synthesizing retinal that is the basic raw material of carotenoids important in the fields of medicines, feed additives, plants, food additives, and so on. SOLUTION: A methoxyalcohol derivative of formula I. The compound of formula I is obtained, for example, by reacting (A) a diol derivative of formula II with methanol in the presence of (B) an acid catalyst [for example, tin (II) chloride, tin (IV) chloride, zinc chloride, iron (III) chloride, a rare earth metal triflate, hydrobromic acid or hydrochloric acid] preferably at -78 deg.C to the boiling point of a solvent to be used to selectively methylate the secondary hydroxyl group. The component B is preferably used in an amount of about 0.01 to 1 mole time that of the component A. Retinal is obtained by oxidizing the compound of formula I with an oxidizing agent such as manganese dioxide to prepare the methoxyaldehyde derivative of formula III, and then removing the methoxy group of the compound of formula III.
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