Potassium Hydroxide → 2,8-dimethyl-5-(2-(5-methylpyrazin-2-yl)ethyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole

HRID 710787

Reaction equation

HRID 710787 reaction equation
[CH3:1][N:2]1[CH2:15][CH2:14][C:5]2[NH:6][C:7]3[CH:8]=[CH:9][C:10]([CH3:13])=[CH:11][C:12]=3[C:4]=2[CH2:3]1.[OH-].[K+].[CH3:18][C:19]1[CH:24]=[N:23][C:22]([CH:25]=[CH2:26])=[CH:21][N:20]=1>CN1CCCC1=O.O>[CH3:1][N:2]1[CH2:15][CH2:14][C:5]2[N:6]([CH2:26][CH2:25][C:22]3[CH:21]=[N:20][C:19]([CH3:18])=[CH:24][N:23]=3)[C:7]3[CH:8]=[CH:9][C:10]([CH3:13])=[CH:11][C:12]=3[C:4]=2[CH2:3]1

Participants

6

Reactant 3

HCID 14797Potassium HydroxideHCID 263352-Methyl-5-vinylpyrazineHCID 2092911H-Pyrido[4,3-b]indole, 2,3,4,5-tetrahydro-2,8-dimethyl-

Product 1

HCID 578759102,8-dimethyl-5-(2-(5-methylpyrazin-2-yl)ethyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indoleYield 31.2%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 13387N-methyl-2-pyrrolidoneSolvent

Procedure

To a solution of 2,8-Dimethyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (0.1 g, 0.5 mmol) in N-methyl 2-pyrolidone (0.75 mL) was added powdered potassium hydroxide (0.281 g, 5.0 mmol) and allowed to stir for 10 min at RT. 2-methyl-5-vinyl pyrazine (0.151 g, 1.2 mmol) was added and stirred for further 2 h. at 60 deg C. After completion (TLC), reaction mixture was diluted with water (25 mL) and extracted with ethyl acetate (3×100 mL). The organic layer was dried over anhydrous sodium sulphate and concentrated under reduced pressure. The crude was purified through column chromatography (6% MeOH:DCM in silica 100-200 mesh, Diameter of column—2.5 cm, Height of silica—approx. 5 inch) to provide the desired compound as yellow oil (0.05 g, 31% yield). 2,8-Dimethyl-5-[2-(5-methyl-pyrazin-2-yl)-ethyl]-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (0.05 g, 0.156 mmol) was dissolved in THF (2.0 mL). A solution of oxalic acid dihydrate (0.015 g, 0.000119 mol) in THF (1.0 mL) was added and stirred for 30 min at RT. Precipitate obtained was filtered and dried to give oxalate salt as white solid (0.03 g, 47% yield).

Workup

  1. stirringstirred for further 2 h. at 60 deg C
  2. customAfter completion (TLC), reaction mixture
  3. extractionextracted with ethyl acetate (3×100 mL)
  4. dry with materialThe organic layer was dried over anhydrous sodium sulphate
  5. concentrationconcentrated under reduced pressure
  6. customThe crude was purified through column chromatography (6% MeOH:DCM in silica 100-200 mesh, Diameter of column—2.5 cm, Height of silica—approx. 5 inch)

Sources & evidence

ORD record
ord-b65c4555e4c64bbf9caaca414636c108
Source dataset
uspto-grants-2015_11
Patent number
US09181240B2

Linked notes

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