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

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Reaction Steps

To a stirred solution of ethyl 4-iodo-1H-pyrazole-3-carboxylate (Step 10.1) (2 g, 7.14 mmol) in THF (40 mL) under Ar was added TurboGrignard (5.77 mL, 7.50 mmol) at −10° C. After 30 min, 4-chlorobenzaldehyde (1.004 g, 7.14 mmol) was added. The reaction mixture was stirred for 60 min at rt, quenched with a saturated aq. NH4Cl solution, and extracted EtOAc. The combined organic layers were washed a saturated aq. NH4Cl solution, dried over Na2SO4 and evaporated. The crude material was purified by silica gel column chromatography (hexane/EtOAc 35-55%) to afford the title product (1.73 g, 5.87 mmol, 82% yield) as a colorless oil. tR: 4.10 min (HPLC 1); tR: 0.89 min (LC-MS 2); ESI-MS: 277/279 [M-18] (LC-MS 2); Rf=0.15 (hexane/EtOAc 1:1).

Provenance & Evidence