Dimethyl Sulfoxide → ethyl 2-methyl-1H-indole-3-carboxylate

HRID 2206464Notes

Reaction equation

CS(C)=O.I[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=1[NH2:12].O=[C:14]([CH3:21])[CH2:15][C:16]([O:18][CH2:19][CH3:20])=[O:17].C(=O)([O-])[O-].[Cs+].[Cs+]>[Cu-]=O.O>[CH3:21][C:14]1[NH:12][C:7]2[C:6]([C:15]=1[C:16]([O:18][CH2:19][CH3:20])=[O:17])=[CH:11][CH:10]=[CH:9][CH:8]=2

Participants

Conditions

Temperature: 100 °C

Procedure

To a mixed solution of dimethyl sulfoxide and water (20 mL), 2-iodobenzenamine (3.0 g, 13.7 mmol), ethyl 3-oxobutanoate (2.0 g, 15.1 mmol), copper(I) oxide (0.2 g, 1.4 mmol) and cesium carbonate (4.5 g, 13.7 mmol) was added. The mixture was stirred at 100° C. for 9 hours under nitrogen gas atmosphere. The reaction mixture was filtered through a pad of celite. The filtrate was diluted with water and extracted with ethyl acetate. The organic phase was concentrated in vacuo, and then the residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=5:1) to give ethyl 2-methyl-1H-indole-3-carboxylate as a light yellow solid (0.42 g, 15%). 1H NMR (300 MHz, CDCl_): δ 8.12-8.09 (m, 1H), 7.31-7.16 (m, 3H), 4.40 (q, J=6.9 Hz, 2H), 2.77 (s, 3H), 1.45 (t, J=6.9 Hz, 3H).

Workup

filtrationThe reaction mixture was filtered through a pad of celite
additionThe filtrate was diluted with water
extractionextracted with ethyl acetate
concentrationThe organic phase was concentrated in vacuo
customthe residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=5:1)

Sources & evidence

ORD record: ord-d7d7446a198e4541af711df947a61511
Source dataset: uspto-grants-2016_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09371331B2

Reaction notes

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