2-Bromopropane → 4-Bromo-1-isopropyl-1H-pyrazole

To a solution of 4-bromo-1H-pyrazole (5 g, 34 mmol) in DMF (70 ml) were added K2CO3 (11.83 g, 85.6 mmol, 2.5 eq.) and 2-bromopropane (6.3 g, 51.36 mmol, 1.5 eq.) and the mixture was stirred at RT for 12 h. The mixture was quenched and extracted as in Intermediate Example 5(a). The solvent was distilled off and the crude residue was purified by column chromatography (60-120 silica gel, 20% ethyl acetate in hexane) to afford the product in 89% yield (5.8 g). 1H NMR (300 MHz, DMSO-d6): δ 8.01 (s, 1H), 7.50 (s, 1H), 4.49-4.43 (m, 1H), 1.38 (d, 6H).

1. customThe mixture was quenched
2. extractionextracted as in Intermediate Example 5(a)
3. distillationThe solvent was distilled off
4. customthe crude residue was purified by column chromatography (60-120 silica gel, 20% ethyl acetate in hexane)
5. customto afford the product in 89% yield (5.8 g)

ORD record

ord-27cb84df084c4cb9be2332bc6cd068a1

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09447091B2