Tetramethoxypropane → 1-(4-Methoxyphenyl)-1H-pyrazole

A mixture of (4-methoxyphenyl)hydrazine hydrochloride (8.0 g, 0.046 mol) and 1,1,3,3-tetramethoxypropane (8.3 g, 0.05 mol) in ethanol (120 mL) was heated to reflux for 1 hour. The reaction was then cooled to room temperature and concentrated. The residue was diluted with saturated sodium bicarbonate (50 mL) and ethyl acetate (100 mL). The phases were separated and the aqueous was extracted with ethyl acetate (2×20 mL). The combined organics were washed with brine (50 mL), dried over sodium sulfate, filtered and concentrated. Purification by column chromatography gave 1-(4-methoxyphenyl)-1H-pyrazole (7.7 g, 97%) as a yellow oil. 1H NMR (400 MHz, CDCl3, δ): 7.82 (m, 1H), 7.69 (m, 1H), 7.59 (d, J=9.2 Hz, 2H), 6.97 (d, J=9.2 Hz, 2H), 6.43 (m, 1H), 3.83 (s, 3H).

1. temperaturewas heated
2. temperatureto reflux for 1 hour
3. concentrationconcentrated
4. additionThe residue was diluted with saturated sodium bicarbonate (50 mL) and ethyl acetate (100 mL)
5. customThe phases were separated
6. extractionthe aqueous was extracted with ethyl acetate (2×20 mL)
7. washThe combined organics were washed with brine (50 mL)
8. dry with materialdried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated
11. customPurification by column chromatography

ORD record

ord-b69a9788c2d24b3a985c9eaee344231d

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08507533B2