Nitric Acid → [3,5-Dimethyl-1-(4-nitro-benzyl)-1H-pyrazol-4-yl]-acetic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

Under cooling, (1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)-acetic acid methyl ester (intermediate 1.1.1, 3.10 g, 12.0 mmol) was dissolved in conc. H2SO4 (7 mL). The mixture was cooled to −7° C. and HNO3 (65%, 0.77 mL) was added dropwise under stirring, keeping the temperature below 0° C. The reaction mixture was allowed to come to room temperature and stirred for 20 min at room temperature. The reaction mixture was poured into ice water, extracted with dichloromethane and the organic layer was concentrated under reduced pressure. The resulting product is a mixture of regioisomers, with the 4-nitro isomer as the main product.

Provenance & Evidence