反应详情

温度

105 °C

2-Nitrophenylhydrazine (3.7 g, 24.2 mmol) and 4-piperidone monohydrate hydrochloride (3.7 g, 24.2 mmol) were suspended in 2,2,2-trifluoroethanol (25 mL). The resultant mixture was heated at reflux for 2 h and then concentrated. Conc. HCl (35 mL) was added in one portion. The resultant mixture was then heated at 105° C. for 15 h, and allowed to cool to rt, after which it was poured onto ice. While vigorously stirring, a 50% NaOH solution was added portionwise over 10 min until pH 12, maintaining the internal temperature at <20° C. The solid was collected via filtration and dried at room temperature under vacuum for 18 h to afford 6-nitro-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (2.91 g, 55%). 1H NMR (300 MHz, DMSO) δ 11.65-11.60 (br s, 1H), 7.96 (d, J=8.1 Hz, 1H), 7.80 (d, J=7.0 Hz, 1H), 7.12 (t, J=8.0 Hz, 1H), 3.86 (s, 2H), 2.99 (br s, 2H), 2.72 (br s, 2H) ppm.

1. temperatureat reflux for 2 h
2. concentrationconcentrated
3. additionConc. HCl (35 mL) was added in one portion
4. temperatureto cool to rt
5. additionafter which it was poured onto ice
6. additiona 50% NaOH solution was added portionwise over 10 min until pH 12
7. temperaturemaintaining the internal temperature at <20° C
8. filtrationThe solid was collected via filtration
9. customdried at room temperature under vacuum for 18 h