Reaktion #6802

Reaktionsgleichung

indole

dimethyl oxalate

Potassium tert-butoxide

→

N-methyl indole

Ausbeute 47.0%

Lösungsmittel

DMF

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigefitted with a condenser
2. 2
   Temperaturthe mixture was heated
3. 3
   Temperaturto reflux for 1 h
4. 4
   Extraktionextracted (4×) with 1:1 hexane/ether
5. 5
   TrocknenThe combined organic extracts were dried over Na2SO4
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated in vacuo
8. 8
   SonstigeThe crude residue was purified by silica gel chromatography (25% EtOAc/hexanes)

Vorschrift

The appropriate indole product prepared using the procedures of Example 38, Step F (41 mg, 0.137 mmol) and dimethyl oxalate (21 mg, 0.17 mmol) were dissolved in DMF (2 mL) under rapid stirring in a 25-mL flask under N2 fitted with a condenser. Potassium tert-butoxide (22 mg, 0.19 mmol) was added, and the mixture was heated to reflux for 1 h. The mixture was cooled to rt, diluted with water (100 mL), and extracted (4×) with 1:1 hexane/ether. The combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo. The crude residue was purified by silica gel chromatography (25% EtOAc/hexanes) to provide the N-methyl indole product (20 mg, 47%) as a yellow oil which solidified upon standing: mp 110-112° C.; 1H NMR (300 MHz, CDCl3) δ 7.11 (d, J=8.3 Hz, 1H), 7.06 (d, J=3.1 Hz, 1H), 6.72-6.80 (m, 3H), 6.59-6.67 (m, 1H), 6.42 (d, J=3.1 Hz, 1H), 4.30 (t, J=5.9 Hz, 1H), 3.95 (d, J=15.3 Hz, 1H), 3.85 (d, J=15.2 Hz, 1H), 3.77 (s, 3H), 3.00 (dd, J=11.3, 5.1 Hz, 1H), 2.71 (dd, J =11.3, 6.6 Hz, 1H), 2.49 (s, 3H); CI MS m/z=313 [C19H18F2N2+H]+; Anal. Calcd. for Cl9Hl8F2N2: C, 73.06; H, 5.81; N, 8.97. Found: C, 72.93; H, 6.08; N, 8.13.

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