Sulfuric Acid → 8-Ethyl-2-methyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole

Reaction equation

S(=O)(=O)(O)O.Cl.[CH2:7]([C:9]1[CH:14]=[CH:13][C:12]([NH:15]N)=[CH:11][CH:10]=1)[CH3:8].[CH3:17][N:18]1[CH2:23][CH2:22][CH2:21][CH2:20][C:19]1=O>O1CCOCC1>[CH2:7]([C:9]1[CH:14]=[CH:13][C:12]2[NH:15][C:21]3[CH2:22][CH2:23][N:18]([CH3:17])[CH2:19][C:20]=3[C:11]=2[CH:10]=1)[CH3:8]

Participants

Procedure

Sulfuric acid is added to a solution of 4-ethyl phenyl hydrazine hydrochloride (1 equiv.) in dioxane, and stirred for 5 min. at RT. N-Methyl piperidone (0.76-1.4 equiv.) is added and the mixture is heated at 80° C. for 3 h. After completion, as monitored by TLC, the reaction mixture is concentrated under reduced pressure and basified to pH 10 using 10% aqueous KOH solution, extracted with EtOAc, dried over anhydrous sodium sulfate and concentrated under reduced pressure using rotary evaporator to provide the desired compound.