5-(Hydroxymethyl)-1,3-Dihydro-2H-Indol-2-One → 2,3-Dihydro-2-oxo-1H-indole-5-carboxaldehyde
Reaction equation
[OH:1][CH2:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[NH:8][C:7](=[O:12])[CH2:6]2>N1C=CC=CC=1.[O-2].[Cr+6].[O-2].[O-2]>[O:12]=[C:7]1[CH2:6][C:5]2[C:9](=[CH:10][CH:11]=[C:3]([CH:2]=[O:1])[CH:4]=2)[NH:8]1Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Procedure
Chromium(VI) oxide (240 mg, 2.4 mmol) was added to ice-cooled pyridine (3 mL). To the formed yellow suspension was added additional pyridine (2 mL) and 5-(hydroxymethyl)-1,3-dihydro-2H-indol-2-one (130 mg, 0.8 mmol) dissolved in pyridine (3 mL). The reaction was quenched after 15 min by the addition of water (50 mL) and extracted with ethyl acetate. The organic phases were dried (Na2SO4) and evaporated in vacuo. The crude product was purified on a silica gel column using methylene chloride/methanol, (10:1), as the eluent to give 60 mg (46% yield) of the title compound.