156835-63-1Relevant academic research and scientific papers
METHOD OF PREPARING (3R,4S)-3-ACETAMIDO-4-ALLYL-N-(TERT-BUTYL)PYRROLIDINE-3-CARBOXAMIDE
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Paragraph 0182; 0183, (2019/01/04)
A method is provided to conveniently separate racemic (3R,4S)-3-acetamido-4-allyl-N-(tert-butyl)pyrrolidine-3-carboxamide and (3S,4R)-3-acetamido-4-allyl-N-(tert-butyl)pyrrolidine-3-carboxamide using selective crystallization with chiral carboxylic acids.
Method for preparing D/L-di(p-toluoyl)tartaric acid
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Paragraph 0019; 0023; 0024, (2017/06/20)
The invention discloses a method for preparing D/L-di(p-toluoyl)tartaric acid, and relates to the technical field of production and processing of di(p-toluoyl)tartaric acid. The main reactions of D/L-di(p-toluoyl)tartaric acid are shown in the specification and include the esterification reaction, centrifuging/washing, hydrolysis, cooling crystallization, centrifuging, drying, recrystallization, centrifuging and drying. The method for preparing D/L-di(p-toluoyl)tartaric acid includes the steps that methylbenzene and tartaric acid are put into an esterification kettle, p-toluoyl chloride and thionyl chloride are dropwise added, and di(p-toluoyl)tartaric anhydride is generated; water is added to hydrolyze the di(p-toluoyl)tartaric anhydride, cooling crystallization, centrifuging and drying are carried out, and a crude product is obtained; a methylbenzene/acetone mixed solvent is added into the crude product, recrystallization and centrifuging are carried out, the solid-phase substances are dried, and the finished product is obtained, wherein distilling recycling of the methylbenzene and the methylbenzene/acetone mixed solvent is carried out in a reaction kettle, condensation is achieved through water cooling and frozen saline water freezing, the recycled methylbenzene solvent is stored through an intermediate tank, and only a small amount of disordered exhaust gas is exhausted.
A D-P-methyl-dibenzoyl tartaric acid synthesis method (by machine translation)
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Paragraph 0034-0036, (2017/03/08)
The invention discloses a Di-p-toluoyl-D-tartaric acid synthetic method. D-Tartaric acid and p-toluoyl chloride are taken as raw materials, copper sulfate is taken as a catalyst, toluene is taken as a solution, Di-p-toluoyl-D-tartaric anhydride is obtained through a reaction, an equivalent amount of water is added, and the toluene is hydrolyzed to obtain Di-p-toluoyl-D-tartaric acid, wherein the toluene solution, and water and the toluene in the hydrolysis can be recycled. The method is simple in process, safe and easy to operate, the process yield reaches over 95 percent; and at the same time, the cost of the raw materials is low, a part of raw material can be recycled, the purity of a finished product is high, and an excellent chiral resolution performance is achieved.
Resolution of (+/-)-propranolol.
Yost,Holtzman
, p. 1181 - 1182 (2007/10/06)
Two improvements in propranolol resolution were developed. Both the (+)- and (-)-di-(p-toluoyl)tartaric acids were used as the resolving agents. This procedure reduced the number of crystallizations needed to obtain a pure product. Furthermore, synthesis of the resolving agent was improved.
