Reaktion #10839

Reaktionsgleichung

5-bromo-2,4-dimethoxybenzaldehyde

H2O2

N-methyl indole

t-BuLi

NaOH

BEt3

→

2,4-dimethoxy-5-(1-methyl-1H-indol-2-yl)-benzaldehyde

Ausbeute 25.0%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe mixture stirred for another 1 hr at room temperature
2. 2
   Temperaturthe mixture was heated to about 60° C. for 30 minutes
3. 3
   workup.STIRRINGstirred for 10 minutes
4. 4
   ExtraktionThe mixture was extracted with EtOAc and combined organic phase
5. 5
   Waschenwas washed with H2O and brine
6. 6
   Trocknendried over MgSO4
7. 7
   Sonstigeabsorbed to small amount of silica gel

Vorschrift

Ex-116A: To a solution of N-methyl indole (1.3 g, 10 mmol) in 50 ml THF, t-BuLi (1.7 m in THF, 7.1 ml, 12 mmol) was slowly added at 0° C. under nitrogen. The mixture was stirred at room temperature for 1 hr, BEt3 (1.0 M in THF, 12 ml, 12 mmol) was added, and the mixture stirred for another 1 hr at room temperature. Then, PdCl2(PPh3)2 (0.35 g, 0.5 mmol) and 5-bromo-2,4-dimethoxybenzaldehyde (3.7 g, 15 mmol) were added, and the mixture was heated to about 60° C. for 30 minutes. The reaction mixture was poured into 50 ml 10% NaOH and treated with 30% H2O2 and then stirred for 10 minutes. The mixture was extracted with EtOAc and combined organic phase was washed with H2O and brine, dried over MgSO4, and absorbed to small amount of silica gel. Column chromatography (EtOAc:Hexane, 1:2) gave 0.72 g (25%) 2,4-dimethoxy-5-(1-methyl-1H-indol-2-yl)-benzaldehyde. 1H-NMR (CDCl3) δ 10.33 (s, 1H), 7.84 (s, 1H), 7.60 (d, J=8 Hz, 1H), 7.31 (d, J=8 Hz, 1H), 7.18–7.24 (m, 1H), 7.07–7.12 (m, 1H), 6.53 (s, 1H), 6.46 (s, 1H), 4.00 (s, 3H), 3.89 (s, 3H), 3.53 (s, 3H). HRMS (EI) Calcd. for C18H17NO3: 295.1208. Found: 295.1202.

Quelle