Hydrochloric Acid → 3-(3-Chloropyrazinyl)-1-azabicyclo[2.2.2]octan-3-ol

Participants

Reaction Conditions

Reaction Steps

A solution of 7.2 ml 2,2,6,6-tetramethylpiperidine (0.034 mol) in 300 ml of dry THF was cooled to -8° C. as 25 ml of 1.6 M butyllithium (0.04 mol) in hexane was added dropwise. The reaction was stirred 20 min then cooled to -77° C. A solution of 2.9 ml of 2-chloropyrazine (0.031 mol) in 5 ml of THF was added to the reaction dropwise. After 15 min, 4.4 g of 3-quinuclidinone (0.0352 mol) in 5 ml of THF was added dropwise and the reaction stirred another 1.5 h. A solution of 8 ml of concentrated HCl and 4 ml of ethanol was added and the cooling was removed. When the temperature reached -5° C., 20 ml of 5 N NaOH was added and the volatile organics were evaporated. The residue was suspended in 50 ml of ice-water and the mixture filtered. The aqueous filtrate was extracted 3× with 50 ml of CHCl3. The extracts were combined with the solid collected from the filtration and the volume of the mixture adjusted to 450 ml with additional CHCl3. The mixture was heated on a steam bath until most of the solid had dissolved. The mixture was dried, filtered, and the solvent evaporated to give a dark brown solid that was recrystallized from isopropanol to give 6.3 g of (7), mp 215°-216° C. NMR ppm (CDCl3) 1.25(1H, m), 1.5 (2H, m), 2.2 (1H, m), 2.65-3.1 (6H, m), 3.6 (1H, bs), 4.05 (1H, d), 8.3 (1H, d), 8.5 (1H, d). Anal. C11H14ClN3O requires C: 55.12; H: 5.89; N: 17.53%. Found C: 55.21; H: 5.99; N: 17.30%.

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