Acetaldehyde → 3-chloro-N-ethyl-1-(pyridin-3-yl)-1H-pyrazol-4-amine

A 3-neck, 100 mL round bottom flask was charged with 3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-amine (5d) (500 mg, 2.57 mmol) and methanol (5 mL) The mixture was stirred for 5 minutes to give a clear solution. Acetaldehyde (136 mg, 3.09 mmol) was added and the reaction was stirred at 20° C. for 6 hours. Sodium borohydride (194 mg, 5.14 mmol) was added and the reaction was stirred at 20° C. for 1 hour, at which point thin layer chromatography analysis [Eluent: ethyl acetate] indicated that some starting material remained and a major product formed. The reaction mixture was quenched with water (10 mL) and concentrated under reduced pressure to remove methanol. Ethyl acetate (10 mL) was added and the organic layer was concentrated to dryness. The residue was purified by flash column chromatography using 20-40% ethyl acetate/hexanes as eluent. The fractions containing pure product were combined and concentrated to afford a white solid (328 mg, 58%). The spectral characterization was in agreement with the product prepared previously.

1. customto give a clear solution
2. stirringthe reaction was stirred at 20° C. for 6 hours
3. customa major product formed
4. customThe reaction mixture was quenched with water (10 mL)
5. concentrationconcentrated under reduced pressure
6. customto remove methanol
7. additionEthyl acetate (10 mL) was added
8. concentrationthe organic layer was concentrated to dryness
9. customThe residue was purified by flash column chromatography
10. additionThe fractions containing pure product
11. concentrationconcentrated

ORD record

ord-f8342088425a4e88a7822a22288c6f80

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09434712B2