Sulfuric Acid → 1H-Pyrido[4,3-b]indole, 2,3,4,5-tetrahydro-2,8-dimethyl-

Participants

Reaction Steps

Sulfuric acid (2 mL) was added to a solution of p-tolyl hydrazine hydrochloride (6.0 g, 37 mmol) in dioxane (60 mL), and stirred for 5 min. at RT. N-Methyl piperidone (5.03 g, 41 mmol) was added and the mixture was heated at 80° C. for 2 h. After reaction completion as determined by TLC), the reaction mixture was concentrated to approximately 20 mL under reduced pressure and basified to pH 10 using 10% aqueous KOH solution. The reaction mixture was extracted with EtOAc (3×300 mL), dried over anhydrous sodium sulfate and concentrated under reduced pressure using a rotary evaporator to provide the desired compound as a brown colored solid (4.0 g, 52% yield). 1H NMR (DMSO-d6, di-HCl salt) δ (ppm): 7.30 (s, 1H), 7.20-7.10 (d, 1H), 7.10-7.00 (d, 1H), 3.80 (s, 2H), 2.90 (s, 4H), 2.60 (s, 3H), 2.40 (s, 3H).

Provenance & Evidence