Sodium Carbonate → 1H-Pyrido(4,3-b)indol-1-one, 2,3,4,5-tetrahydro-5-methyl-

Participants

Reaction Steps

3,4-Dihydro-4-methylcyclopent[b]indol-1(2H)-one oxime (1.53 g), polyphosphoric acid (40 g) and dioxan (15 ml) were heated at 110°-120° for 2.2h under nitrogen. The reaction mixture was cooled, and treated with 2N sodium carbonate solution (`l). The suspension was extracted with ethyl acetate (4×400 ml) and the combined extracts were dried. Evaporation gave a solid (1.43 g) which was recrystallised from ethyl acetate/cyclohexane. This solid was purified by FCC, eluting with System A (200:10:1) to give a solid (1.26 g) which was recrystallised from ethanol to provide the title compound (960 mg), m.p. 234°-238°.

Provenance & Evidence