Takeda Chemical Industries, Inc.

Mitsutaka Tanaka

Kunio Takanohashi

Toru Yamano

Tadashi Hanaoka

L-ascorbic acid is produced by allowing an acid to act on 2-keto-L-gulonic acid in a mixture solvent of an inert organic solvent and an aliphatic ketone in the presence of water and a surfactant. The method produces L-ascorbic acid in a high yield 90% or more and is an industrially advantageous method.

Production of L-ascorbic acid

The present specification relates to an industrially advantageous process for producing vitamin A derivatives which are useful as medicaments, feed additives, food additives and the like. The process provides vitamin A derivatives, particularly all-trans vitamin A derivatives in high yield and purity.

Process for producing vitamin A derivatives

6-O-(2-keto-L-gulonoyl)-L-ascorbate substantially free from 2-keto-L-gulonic acid is produced by allowing an acid to act on 2-keto-L-gulonic acid in an inert organic solvent and recovering 6-O-(2-keto-L-gulonoyl)-L-ascorbate from the reaction mixture. 6-O-(2-keto-L-gulonoyl)-L-ascorbate is more fat-soluble than L-ascorbic acid and is expected of the use as a prodrug for L-ascorbic acid that can be absorbed from the intestinal tract.

Ascorbic acid ester

A novel 2-lower alkyl-4-amino-5-substituted iminopyrimidine compound represented by the formula: ##STR1## wherein R is a lower alkyl, and Y is hydroxyl or amino which may be protected or a salt thereof is obtainable by allowing a formylpyrimidine compound represented by the formula: ##STR2## wherein R is a lower alkyl to react with a compound represented by the formula H.sub.2 N--Y, wherein Y is hydroxyl or amino which may be protected, or a salts thereof. The iminopyrimidine compound gives the known pyrimidine compound represented by the formula: ##STR3## wherein R is as defined above in high yield. Therefor, the process is very useful as an industrial production method.

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Sanda, Japan

Mitsutaka Tanaka