2,3-Dihydroxybutanedioic Acid → HCID 11679825, 화합물

In the same manner as in a document (Mi, Y.; Corey, E. J. Tetrahedron Lett. 2006, 47, 2515-2516), optical resolution by a diastereomer salt method was performed to synthesis the title compound. That is, to a solution of 1-azabicyclo[2.2.2]octane-2-carbonitrile (20.0 g) produced in Example 164, step E, in methanol (100 mL) was slowly added a solution of (+)-tartaric acid (22.0 g) in methanol (100 mL) at 0° C. The reaction system was stirred for 90 min, and concentrated, and the obtained solid was crystallized 4 times from methanol to give (+)-tartrate of (2S)-1-azabicyclo[2.2.2]octane-2-carbonitrile (3.0 g, >90% ee). To the obtained solid was added water (50 mL), and sodium hydrogen carbonate was added to reach pH 8. The mixture was extracted with dichloromethane (100 mL×3), and the extract was washed with brine, dried, and concentrated. The obtained white solid (1.4 g) was dissolved in concentrated hydrochloric acid (50 mL), and the reaction mixture was heated under reflux overnight. After concentration, to the residue was slowly added a solution of sodium hydroxide (0.83 g) in water (10 mL) at 0° C. The mixture was concentrated, concentrated hydrochloric acid (5 mL) was added, and the mixture was concentrated again. The obtained white solid was extracted with methanol (10 mL). Insoluble material was filtered off, and the filtrate was concentrated to give the title compound (1.7 g).