Process for preparing D-proline

Abstract

A process for preparing D-proline includes such steps as mixing L-proline with D-tartaric acid, dissolving in organic acid, adding catalyst, stirring at 80+ / -10 deg.c for 4-8 hr, cooling in ice water bath, filtering, washing with absolute alcohol, drying, recrystallizing in alcohol to obtain salt of D-tartaric acid. D-proline, dissolving it in methanol, stirring at 20-65 deg.c while adding aminating agent until the solution shows weak alkaline, stirring, cooling to 5-10 deg.c, filtering out ammonium D-tartarate, removing methanol from mother liquid, and recrystallizing.

Description

1. Technical field: [0001] The invention is a method for preparing chiral organic compounds, especially a method for preparing D-proline. 2. Background technology: [0002] D-amino acid is an important class of chiral reagents and chiral intermediates. At present, most of the production of D-amino acid is to prepare the racemate by synthetic method, and then carry out the resolution to obtain the optical isomer. Therefore, the resolution of racemic amino acids is an important step in the production of D-amino acids. [0003] One of the most commonly used separation methods for racemic amino acids is the chemical resolution method. Even if the racemic amino acid reacts with a chiral reagent to form diastereomers, they are separated by utilizing the differences in physical and chemical properties of the diastereomers. Amino acids contain both acidic groups and basic groups, and are amphoteric compounds. Therefore, the most convenient way is to make them react with asymmetric...

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: the total yield is low; in the resolution step, there will be entrainment and separation of diastereoisomers, resulting in a reduction in optical purity; adding a racemization step, the operation increases, and various aspects increased consumption

The Japanese Shiraiwa et al. have reported the process of preparing D-proline by asymmetric transformation method, but the consumption of raw materials and solvents is large, it is not easy to obtain pure products, and it has no practical significance in industrial production.