Water → [3,5-diethyl-1-(4-nitro-benzyl)-1H-pyrazol-4-yl]acetic acid ethyl ester

Participants

Reaction Steps

To a solution of (3,5-diethyl-1H-pyrazol-4-yl) acetic acid ethyl ester (10.95 g, 52.1 mmol) and 4-nitrobenzyl bromide (14.625 g, 68 mmol) in acetonitrile (110 mL) is added K2CO3 (10.80 g, 78.1 mmol) and the mixture is stirred for 48 hours at room temperature. The reaction mixture is poured into water and extracted twice with ethyl acetate. The organic phase is dried over MgSO4 and evaporated under reduced pressure. The residue is purified by MPLC with ethyl acetate/cyclohexane to yield 12.50 g [3,5-diethyl-1-(4-nitro-benzyl)-1H-pyrazol-4-yl]acetic acid ethyl ester (ESI mass spectrum: [M+H]+=346; Retention time HPLC: 1.42 min (method B)). b) To a solution of [3,5-diethyl-1-(4-nitro-benzyl)-1H-pyrazol-4-yl]acetic acid ethyl ester (6.66 g, 19.3 mmol) in methanol (500 mL) is added Raney nickel (500 mg) and the mixture is hydrogenated at 50 psi and room temperature. The catalyst is filtered off and the filtrate is concentrated under reduced pressure to yield 4.38 g of the title compound (ESI mass spectrum: [M+H]+=316; Retention time HPLC: 1.09 min (method B)).

Provenance & Evidence