A METHOD FOR PREPARING 4-[9-(6-AMINOPURINE)]-2-(S)-HYDROXYL-BUTYRIC ACID METHYL ESTER

摘要

The invention discloses a novel method for preparing and purifying 4-[9-(6-aminopurine)]-2-(S)-hydroxyl-butyric acid methyl ester. The said method starts with cheap and easily available L-malic acid, both of 1-carboxyl and 2-hydroxyl are protected to get intermediate I; the intermediate I is selectively reduced to intermediate alcohol II; the hydroxyl in the intermediate alcohol II is converted to easily removable group and intermediate III is obtained; the nucleophilic substitution reaction of the intermediate III and adenine is conducted to give intermediate IV; the deprotection and methyl esterification of the intermediate IV are accomplished at the same time in methanol and under the action of acid or alkali to obtain the crude product of 4-[9-(6-aminopurine)]-2-(S)-hydroxyl-butyric acid methyl ester, and the pure product is obtained after the crude product is purified by recrystallization. Compared with the existing preparing method, the present technique has the features of low cost, mild conditions, chiral center not easily being racemized in the reaction course, high production efficiency and so on. The quality and yield of the product are both increased greatly, the cost is lowered to a great extent, and thus the present method is suitable for preparation on a large scale.