Sodium ethoxide → 3,4,6,7,8,9-Hexahydropyrazino[1,2-a]indol-1(2H)-one

Temperature

55 °C

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet was purged with nitrogen and charged with 101d (1.80 g, 7.63 mmol), sodium ethoxide (1.55 g, 22.8 mmol) and ethanol (50 mL). The mixture was stirred at 55° C. for 5 h. After that time, the reaction mixture was concentrated under reduced pressure and the residue was partitioned between ethyl acetate (200 mL) and water (100 mL). The organic layer was separated, and the aqueous layer was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography to afford a 42% yield (605 mg) of 3,4,6,7,8,9-hexahydropyrazino[1,2-a]indol-1(2H)-one 101e as a white solid: mp 207-209° C.; 1H NMR (500 MHz, DMSO-d6) δ 7.41 (s, 1H), 6.36 (s, 1H), 3.84 (t, 2H, J=6.0 Hz), 3.42 (m, 2H), 2.51 (t, 2H, J=6.0 Hz), 2.42 (t, 2H, J=6.0 Hz), 1.76 (m, 2H), 1.65 (m, 2H); (APCI+) m/z 191.3 (M+H)

1. customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and nitrogen inlet
2. customwas purged with nitrogen
3. concentrationAfter that time, the reaction mixture was concentrated under reduced pressure
4. customthe residue was partitioned between ethyl acetate (200 mL) and water (100 mL)
5. customThe organic layer was separated
6. extractionthe aqueous layer was extracted with ethyl acetate (2×100 mL)
7. washThe combined organic layers were washed with brine
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated under reduced pressure
10. customThe residue was purified by column chromatography

ORD record

ord-a75c4c4227364415ba2d005fc7c34421

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08921353B2