The general procedure for the synthesis of di-p-toluoyltartaric acid and compound (CAS: 243640-19-9) from compound (CAS: 869749-09-7) was as follows: (R)-α-(2,3-dimethoxyphenyl)-4-piperidine methanol was mixed with (2R,3R)-(-)-di-(p-toluoyl)tartaric acid salt (7 g) in 10 mL of concentrated ammonia and methanol were stirred well. After 2 hours of reaction, 30 mL of water was added and evaporated to remove methanol and ammonia. Subsequently, another 30 mL of water was added and the precipitate was collected, rinsed with water and dried to give (R)-α-(2,3-dimethoxyphenyl)-4-piperidine methanol (1), which typically has an enantiomeric excess of 85% (ee). After acidification of the aqueous layer with 1N hydrochloric acid, the precipitate was collected and dried to recover (2R,3R)-(-)-di-(p-toluoyl)tartaric acid.
![Butanedioic acid, 2,3-bis[(4-methylbenzoyl)oxy]-, (2R,3R)-, compd. with (αR)-α-(2,3-dimethoxyphenyl)-4-piperidinemethanol (1:1)](/CAS/20210305/GIF/869749-09-7.gif)
