Phosphorus oxychloride → 1,3-dimethyl-1H-indole-2-carbaldehyde

HRID 2097188Notes

Reaction equation

P(Cl)(Cl)(Cl)=O.[CH3:6][N:7]1[C:15]2[C:10](=[CH:11][CH:12]=[CH:13][CH:14]=2)[C:9]([CH3:16])=[CH:8]1.[C:17]([O-])(=[O:19])C.[Na+]>CN(C=O)C>[CH3:6][N:7]1[C:15]2[C:10](=[CH:11][CH:12]=[CH:13][CH:14]=2)[C:9]([CH3:16])=[C:8]1[CH:17]=[O:19]

Participants

Conditions

Temperature: 99 °C

Procedure

Phosphorous oxychloride (0.0.93 mL, 9.7 mmol) was added dropwise with stirring to DMF (5 mL) at 10° C. over 20 min. 1,3-dimethyl-1H indole (1.3 g mg, 8.9 mmol) in DMF (5 mL) was added slowly with stirring and the mixture was heated for 3 h at 98-100° C. Excess concentrated aqueous solution of sodium acetate was added. The mixture was stirred for 30 min at 28° C. and extracted with ethyl acetate, dried and evaporated. The crude mixture was chromatographed over silica gel eluting with hexane/ether to afford the title compound (1.5 g, 97%). 1H NMR (400 MHz, DMSO-d6) δ 10.15 (s, 1H), 7.74 (d, J=7.6 Hz, 1H), 7.53 (d, J=7.8 Hz, 1H), 7.42 (t, J=8.0 Hz, 1H), 7.15 (t, J=7.6 Hz, 1H), 3.99 (s, 3H), 2.60 (s, 3H)

Workup

stirringThe mixture was stirred for 30 min at 28° C.
extractionextracted with ethyl acetate
customdried
customevaporated
customThe crude mixture was chromatographed over silica gel eluting with hexane/ether

Sources & evidence

ORD record: ord-1c1130279ace4ab88e9ec1974fa99420
Source dataset: uspto-grants-2013_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08450307B2

Reaction notes

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