Potassium Carbonate → HCID 178526587, compound

Participants

Reaction Steps

A suspension of 1-acetyl-3-hydroxy-pyrazole (3.4 g, 27.0 mmol), 2-nitrobenzyl bromide (5.9 g, 27.3 mmol) and K2CO3 (4.0 g, 28.9 mmol) in 75 mL of 2-butanone was heated to reflux for 90 min. After cooling to room temperature, the precipitated salts were filtered off and rinsed with tert-butyl methyl ether (TBME). The filtrate was then concentrated under reduced pressure (50 mbar) and redissolved in a mixture of tetrahydrofuran (THF) and methanol (MeOH) (3:2, 50 mL). 2 mL of a 10% NaOH solution were added and the solution was stirred 60 min at ambient temperature. Then, all volatiles were removed under reduced pressure (50 mL). The residue was diluted with 20 mL of H2O and 30 mL of ethyl acetate (EtOAc). The aqueous phase was extracted with EtOAc (2×20 mL). The combined org. layers were washed with water and brine (both 30 mL) and dried over Na2SO4. The crude product was obtained after evaporation of all volatiles and recrystallised from dichloromethane (15 mL) to give the product as yellowish crystals (5.0 g, 22.8 mmol, 84%).

Provenance & Evidence