Method for preparing and purifying 2,3-O-isopropylidene threitol

Abstract

The invention discloses a method for preparing and purifying 2,3-O-isopropylidene threitol. The preparation method comprises the following steps of uniformly mixing 2,3-O-isopropylidene diethyl tartrate, a solvent and a reducer at 0-5 DEG C, preserving heat at 0-70 DEG C, performing reduction reaction for 16-36 hours, preserving heat, and adding a quenching agent for quenching reaction to obtain 2,3-O-isopropylidene threitol. The purification method comprises the steps of performing reduced pressure distillation on a crude product of 2,3-O-isopropylidene threitol, collecting fractions at 140-170 DEG C, uniformly dispersing the fractions with ethanol, adding dry ice, uniformly mixing, and separating out white solids, namely purified 2,3-O-isopropylidene threitol. The method is simple in process, low in production cost and high in product yield, and has an important application value.

Description

technical field [0001] The invention relates to a method for preparing and purifying 2,3-O-isopropylidene threitol. Background technique [0002] 2,3-O-isopropylidene threitol is a widely used chiral pharmaceutical intermediate, and its preparation is usually prepared by the reaction of dimethyl tartrate and 2,2-dimethoxypropane 2,3-O-Dimethyl isopropylidene tartrate can be obtained by reduction with lithium aluminum hydride or sodium borohydride. At present, the most selected method in literature reports is reduction with lithium aluminum hydride or red aluminum reagent. The advantage of this method is that there are few by-products in the reduction reaction and the yield is high. The disadvantage is that the reducing agent is relatively expensive and the cost is high. Another literature report, sodium borohydride in the methanol system, can be reduced to obtain a higher yield of the product. However, the post-treatment of this type of reaction is cumbersome, and it is ne...

AI Technical Summary

Problems solved by technology

[0003] At present, after retrieving domestic and foreign reports, it is basically certain that there is no large-scale industrial production of high-quality 2,3-O-isopropylidene threitol. The main difficulty is that no matter what method is used for reduction, a certain amount of If there is too much water, the product needs to be extracted from the water, and more organic solvents are needed, so the solvent consumption is large, the yield is low, and the production process is cumbersome

In addition, most of the purifications reported in the literature use column chromatography, but the efficiency and cost of column chromatography are very limited in industry, and it is not easy to scale up production

There are only very few reports using high-efficiency vacuum pumps for distillation, and the vacuum degree is required to be 0.5mmHg, which is difficult to achieve in industry