Sulfuric Acid → 6-Chloro-2-methyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole

Participants

Reaction Conditions

Reaction Steps

To a suspension of 2-chlorophenyl hydrazine hydrochloride (19.7 g, 0.110 mol) in dioxane (190 mL) at RT was added conc. H2SO4 (8 mL, 0.150 mol) dropwise and the reaction mixture was stirred for 10 min. To this was added N-methyl-4-piperidone (17.53 g, 0.154 mol) and the reaction mixture was stirred at RT for 20 min, then heated at 80° C. for 4 h. The reaction was monitored by TLC. The solvent was evaporated and pH adjusted to pH 8-9 with saturated sodium bicarbonate solution. The product was extracted with EtOAc (3×300 mL). The combined organic layer was washed with water and brine, dried over sodium sulfate, and concentrated under vacuum. The crude product was purified by recrystallization (Ether/Hexane). The filtered solid was dried in vacuo to obtain 7.5 g of product as a brown solid. 1H NMR (CDCl3, freebase) d (ppm): 8.10 (bs, 1H), 7.30 (d, 1H), 7.10 (d, 1H), 7.0 (t, 1H), 3.62 (s, 2H), 2.90 (m, 2H), 2.82 (m, 2H), 2.38 (s, 3H).

Provenance & Evidence