反应详情

(R)-Tetrahydro-furan-2-carboxylic acid (1-benzyl-piperidin-4-yl)-amide (128 g, 444 mmol) was dissolved in 300 mL ethanol and 50 mL acetic acid. Palladium on activated carbon (5 g) was added. A hydrogen pressure of 5 bars was applied, and hydrogenation was continued until no more hydrogen was consumed (about 5 days). The suspension was filtered through Celite, and the filtrate was evaporated to dryness under reduced pressure. The residue and oxalic acid (50 g, 555 mmol) were suspended in 500 mL 2-propanol and heated to dissolve the solids. Upon cooling, the oxalate salt of R-tetrahydro-furan-2-carboxylic acid piperidin-4-ylamide crystallized and was collected by filtration to yield (R)-Tetrahydro-furan-2-carboxylic acid piperidin-4-ylamide as an oxalate salt (99.0 g, 77%) as an off-white solid. 1H-NMR (300 MHz, DMSO-d6): δ 7.84 (d, J=7.8 Hz, 1H), 5.90 (bs, 2H), 4.18-4.14 (m, 1H), 3.89-3.67 (m, 3H), 3.25-3.20 (m, 2H), 2.94-2.71 (m, 2H), 2.13-2.00 (m, 1H), 1.56-1.58 (m, 6H) ppm.

1. customwas consumed (about 5 days)
2. filtrationThe suspension was filtered through Celite
3. customthe filtrate was evaporated to dryness under reduced pressure
4. temperatureheated
5. dissolutionto dissolve the solids
6. temperatureUpon cooling
7. customthe oxalate salt of R-tetrahydro-furan-2-carboxylic acid piperidin-4-ylamide crystallized
8. filtrationwas collected by filtration