Sulfuric Acid → 1H-Pyrido[4,3-b]indole, 2,3,4,5-tetrahydro-2,8-dimethyl-
Reaction equation
S(=O)(=O)(O)O.Cl.[C:7]1([CH3:15])[CH:12]=[CH:11][C:10]([NH:13]N)=[CH:9][CH:8]=1.[CH3:16][N:17]1[CH2:22][CH2:21][CH2:20][CH2:19][C:18]1=O>O1CCOCC1>[CH3:16][N:17]1[CH2:22][CH2:21][C:20]2[NH:13][C:10]3[CH:9]=[CH:8][C:7]([CH3:15])=[CH:12][C:11]=3[C:19]=2[CH2:18]1Participants
Procedure
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).
Workup
- temperaturethe mixture was heated at 80° C. for 2 h
- customAfter reaction completion
- concentrationwas concentrated to approximately 20 mL under reduced pressure and basified to pH 10
- extractionThe reaction mixture was extracted with EtOAc (3×300 mL)
- dry with materialdried over anhydrous sodium sulfate
- concentrationconcentrated under reduced pressure
- customa rotary evaporator
Sources & evidence
- ORD record
- ord-7b4ce8c3659e47a8a0e4b9f305fd34fc
- Source dataset
- uspto-grants-2014_12
- Patent number
- US08907097B2
Reaction notes
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