Formaldehyde → HCID 114844633, compound

Participants

Reaction Steps

1-(2-bromo-5-chlorophenyl)-3-methyl-1H-pyrazole/1-(2-bromo-5-chlorophenyl)-5-methyl-1H-pyrazole mixture (Intermediate 3, step 1) (1.00 g, 3.68 mmol) was dissolved in THF (6 mL) then cooled to 0° C. i-Propyl magnesium chloride (2.76 mL, 2.0 M in THF, 5.52 mmol) was added dropwise and the reaction was warmed to RT for 30 min. The reaction was then cooled to −15° C. and paraformaldehyde (166 mg, 5.5 mmol) was added. The reaction mixture was allowed to warm to RT and stirred for 1 h. DMF (500 mL) was added and the reaction was stirred for an additional 1 h. The reaction was quenched with HCl (2 N, 4 mL), diluted with water, extracted with EtOAc, washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. Purification by normal phase silica gel column chromatography (EtOAc/heptane) provided 4-chloro-2-(3-methyl-pyrazol-1-yl)-benzaldehyde.

Provenance & Evidence