反应详情

5% Palladium on carbon (16.3 g, 50% wet, 3.83 mmol, Aldrich 330116) was placed in a Parr bottle under nitrogen, followed by MeOH (100 mL, JT-Baker 909333). The crude mixture of 2-(2-nitrophenyl)-2,5-dihydrofuran and 2-(2-nitrophenyl)-2,3-dihydrofuran (3a & 3b) (163 g) dissolved in MeOH (389 mL) was added to the Parr bottle, followed by NEt3 (237.6 mL, 1.705 mol, Sigma-Aldrich 471283). The bottle was placed on a Parr shaker and saturated with H2. 30 psi H2 was added and the bottle was shaken until starting material was completely consumed (LCMS and NMR showed complete reaction). The reaction mixture was purged with nitrogen, filtered through Celite™ and rinsed with EtOAc. The filtrate was concentrated on a rotary evaporator giving a brown oil. The reaction was repeated three more times on the same scale and the batches were combined for purification. The crude product was vacuum distilled (ca. 15 torr) collecting the distillate at 108-129° C. to give (4) as a clear faint yellow oil (427.9 g, average yield was 84%; 98% GCMS purity). LCMS (C18 column eluting with 10-90% CH3CN/water gradient over 5 minutes with formic acid modifier) M+1: 163.95 (1.46 min). 1H NMR (300 MHz, CDCl3) δ 7.15-7.04 (m, 2H), 6.77-6.62 (m, 2H), 4.85-4.77 (m, 1H), 4.18 (s, 2H), 4.12-4.02 (m, 1H), 3.94-3.85 (m, 1H), 2.25-1.95 (m, 4H) ppm.

1. additionwas added to the Parr bottle
2. addition30 psi H2 was added
3. customwas completely consumed
4. custom(LCMS and NMR showed complete reaction)
5. customThe reaction mixture was purged with nitrogen
6. filtrationfiltered through Celite™
7. washrinsed with EtOAc
8. concentrationThe filtrate was concentrated on a rotary evaporator
9. customgiving a brown oil
10. customthe batches were combined for purification
11. distillationdistilled (ca. 15 torr)
12. distillationcollecting the distillate at 108-129° C.