4-Chlorobenzaldehyde → ethyl 4-((4-chlorophenyl)(hydroxy)methyl)-1-(4-methoxybenzyl)-5-methyl-1H-pyrazole-3-carboxylate

Participants

Reaction Steps

To a stirred solution of ethyl 4-iodo-1-(4-methoxybenzyl)-5-methyl-1H-pyrazole-3-carboxylate (Step 1.2) (6.23 g, 15.57 mmol) in THF (100 mL) under Ar was added TurboGrignard (15.57 mL, 20.24 mmol) at −10° C. After 15 min, 4-chlorobenzaldehyde (2.188 g, 15.57 mmol) was added. The reaction mixture was stirred for 30 min at this temperature, quenched with a saturated aqueous solution of NH4Cl (50 mL), extracted with EtOAc (2×50 mL). The combined organic layers were washed with a saturated aqueous solution of NH4Cl (75 mL), dried over Na2SO4 and evaporated. The crude material was purified by silica gel column chromatography (hexane/EtOAc 20-50%) to afford the title product (4.50 g, 10.85 mmol, 70% yield) as a colorless oil. tR: 5.34 min (HPLC 1); tR: 1.15 min (LC-MS 2); ESI-MS: 415 [M+H]+ (LC-MS 2); Rf=0.40 (hexane/EtOAc 1:1).

Provenance & Evidence