Dimethylformamide → 1-Methyl-5-(p-tolyl)-1H-pyrazole-4-carbaldehyde

N,N-Dimethylformamide (300 mL) was cooled to 0° C. and treated with phosphorus oxychloride (80 g, 0.52 mol). After completion of the addition, the resulting mixture was warmed to room temperature and stirred for 1 hour. 5-(4-Methylphenyl)-1-methyl-1H-pyrazole (C2) (30.0 g, 174 mmol) was added and the reaction mixture was heated to 120° C. and stirred overnight. The mixture was cooled to room temperature and concentrated in vacuo. The residue was poured into ice-water (700 mL), then adjusted to a pH of approximately 8 with saturated aqueous sodium carbonate solution. The resulting mixture was extracted with dichloromethane (4×300 mL); the combined organic layers were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered, and concentrated under reduced pressure. Purification by silica gel chromatography (Gradient: 1:100 to 1:30 ethyl acetate in petroleum ether) afforded the product as a yellow solid. Yield: 28.2 g, 141 mmol, 81%. 1H NMR (400 MHz, CDCl3) δ 2.46 (s, 3H), 3.81 (s, 3H), 7.33 (br AB quartet, JAB=8 Hz, ΔνAB=17 Hz, 4H), 8.04 (s, 1H), 9.60 (s, 1H).

1. additionAfter completion of the addition
2. temperaturethe reaction mixture was heated to 120° C.
3. stirringstirred overnight
4. temperatureThe mixture was cooled to room temperature
5. concentrationconcentrated in vacuo
6. additionThe residue was poured into ice-water (700 mL)
7. extractionThe resulting mixture was extracted with dichloromethane (4×300 mL)
8. washthe combined organic layers were washed with saturated aqueous sodium chloride solution
9. dry with materialdried over sodium sulfate
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure
12. customPurification by silica gel chromatography (Gradient: 1:100 to 1:30 ethyl acetate in petroleum ether)

ORD record

ord-759f2aa3d6f146988458c8b3b956aef2

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08829010B2