Dimethylformamide → 3-Formyl-2-methylindole

HRID 570618Notes

Reaction equation

HRID 570618 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, 1 N 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). 13C NMR (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-4951c35606544246bfbf1ee97e9c95fc
Source dataset
uspto-grants-2015_05
Patent number
US09023871B2

Reaction notes

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