Hydrochloric Acid → 1-Methylindole

The indole product from Example 56 (100 mg, 0.36 mmol) and dimethyl oxalate (46 mg, 0.39 mmol) in DMF (3 mL) were treated with potassium t-butoxide (44 mg, 0.39 mmol). The reaction was heated at reflux for 30 min. Reaction was cooled to room temperature and diluted with water (25 mL). Following extractions (3×) with ethyl acetate, the organic layers were washed with water, brine, dried over sodium sulfate, filtered and concentrated. The dark residue was chromatographed (SiO2, 20% EtOAc/hexanes), and the resulting oil was treated with 1 M HCl (1 eq) in diethyl ether to provide the N-methyl indole product as a white solid (45 mg, 11%): mp 255-258° C.; 1H NMR (300 MHz, CD3OD) δ 7.43-7.25 (m, 3H), 7.12-7.00 (m, 2H), 6.99 (d, J=10.0 Hz, 1H), 6.70 (d, J=8.6 Hz, 1H), 6.50 (d, J=3.1 Hz, 1H), 4.80-4.67 (m, 2H), 3.89 (dd, J=5.6, 11.9 Hz, 1H), 3.81 (s, 3H), 3.65-3.55 (m, 1H), 3.30-3.29 (m, 1H), 3.14 (s, 3H); IR (KBr) 3424, 2944, 2479, 1590, 1449 cm−1; CI MS m/z=295 [C19H19FN2+H]+.

1. temperatureThe reaction was heated
2. temperatureat reflux for 30 min
3. customReaction
4. extractionextractions (3×) with ethyl acetate
5. washthe organic layers were washed with water, brine
6. dry with materialdried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customThe dark residue was chromatographed (SiO2, 20% EtOAc/hexanes)

ORD record

ord-ccc6e315b0734760bd2eddf77c0f3649

Source dataset

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07084152B2