Dimethylformamide → 3-Formyl-2-methylindole

HRID 571561Notes

Reaction equation

HRID 571561 reaction equation
O=P(Cl)(Cl)Cl.[CH3:6][C:7]1[NH:8][C:9]2[C:14]([CH:15]=1)=[CH:13][CH:12]=[CH:11][CH:10]=2.[OH-].[Na+].CN([CH:21]=[O:22])C>>[CH3:6][C:7]1[NH:8][C:9]2[C:14]([C:15]=1[CH:21]=[O:22])=[CH:13][CH:12]=[CH:11][CH:10]=2

Participants

5

Reactant 4

HCID 6228Dimethylformamide2×HCID 72242-MethylindoleHCID 14798Sodium HydroxideHCID 24813Phosphorus oxychloride

Product 1

HCID 731663-Formyl-2-methylindoleYield 89%

Procedure

To a dried 300 mL two-neck round bottom flask under argon at 0° C., N,N-dimethylformamide (3 mL) was added, followed by POCl3 (1.05 mL, 11.3 mmol). After stirring for ten minutes, 2-methylindole (1.23 g, 9.37 mmol) dissolved in DMF (6 mL) was added dropwise via an addition funnel under argon. After two hours, 1N NaOH (70 mL) was added slowly, upon which a white precipitate formed. The solid was filtered and dried under vacuum, yielding 1.32 g (89%) of white solid. 1H NMR (600 MHz, d6-DMSO): δ 11.998 (s, 1H, N—H), 10.050 (s, 1H, CHO), 8.044-8.032 (d, J=7.2, 1H, indole-4H), 7.388-7.375 (d, J=7.8, 1H, indole-7H), 7.183-7.135 (m, 2H, indole-5,6H), 2.679 (s, 3H, methyl). 13CNMR (150 MHz, d6-DMSO): δ 184.3, 148.6, 135.4, 125.6, 122.7, 121.9, 120.0, 113.7, 111.4, 11.5. Melting Point: 195-200° C. TLC (ethyl acetate:hexanes 4:1) Rf=0.39. Elemental analysis calculated for C10H9NO: C, 75.45; H, 5.70; N, 8.80. found: C, 75.23; H, 5.70; N, 8.93.

Workup

  1. additionwas added dropwise via an addition funnel under argon
  2. customformed
  3. filtrationThe solid was filtered
  4. customdried under vacuum

Sources & evidence

ORD record
ord-c4008c8803ee47c8b9f51d378dffb444
Source dataset
uspto-grants-2015_05
Patent number
US09028796B2

Reaction notes

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