Ethanol → 1-[5-bromo-2-(2-hydroxyethyl)-4-nitro-2H-pyrazol-3-yl]pyrrolidin-3-ol

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-(3,5-dibromo-4-nitropyrazol-1-yl)ethanol (3) (6.5 g, 21 mmol) and pyrrolidinol (3.75 g, 42 mmol) in EtOH (130 ml) was heated at 60° C. for 15 hours. The reaction was stopped after 67% conversion (monitoring by TLC and HPLC) by evaporating off the solvent under reduced pressure at 40° C. (rotary evaporator). The liquid obtained was purified by column chromatography (gradient of from 5%/95% EtOAc/hexane to 20%/80% EtOAc/hexane). The yellow solid obtained (3.9 g) was recrystallized from EtOH to give 1-[5-bromo-2-(2-hydroxyethyl)-4-nitro-2H-pyrazol-3-yl]pyrrolidin-3-ol (4) in the form of a yellow solid (3.5 g, 53%).

Provenance & Evidence