反应详情

1,8-Diethyl-4-hydroxy-1,3,4,9-tetrahydro[3,4-b]indole-1-acetic acid methyl ester 15 (2.5 g, 8.0 mmol) was added in one portion to a suspension of manganese dioxide (15 g) in 150 mL of ether. The solution was allowed to stir at room temperature for 16 hours, after which time an extra 2 g of manganese dioxide was added and the mixture allowed to stir an additional 2 hours to complete the reaction. The manganese dioxide was removed by filtration through celite, and the pad was washed with 500 mL of CH2Cl2. The solvent was concentrated in vacuo to provide 2.2 g of crude solid, which was recrystallized from hot EtOAc-hexane to yield 1.45 g of colorless crystals, m.p. 192°-193° C. Concentration of the mother liquor provided a second crop (210 mg) of crystals for a total yield of 64%. 1H NMR (400 MHz, DMSO-d6): δ 7.77 (d, J=7, 1H), 7.14 (t, J=7, 1H), 7.07 (d, J=7, 1H), 4.27 (d, J=17, 1H), 4.21 (d, J=17, 1H), 3.52 (s, 3H), 3.31 (s, 2H), 2.90 (m, 2H), 2.23 (m, 1H), 1.88 (m, 1H), 1.25 (t, J=7.5, 3H), 0.81 (t, J=7, 3H);

1. stirringto stir an additional 2 hours
2. customthe reaction
3. customThe manganese dioxide was removed by filtration through celite
4. washthe pad was washed with 500 mL of CH2Cl2
5. concentrationThe solvent was concentrated in vacuo
6. customto provide 2.2 g of crude solid, which
7. customwas recrystallized from hot EtOAc-hexane