Dimethylformamide → 1-(2,2-Dimethyl-propyl)-1H-pyrazole-4-carbaldehyde

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Reaction Conditions

Reaction Steps

A flask charged with anhydrous DMF (400 mL) was cooled to 0° C., to which phosphorous oxychloride (114 g, 0.74 mol) was added dropwise, and the temperature was kept below 10° C. The stirring was continued for 1 h and it was allowed to rise to room temperature. Then it was cooled to 0° C. again, and a solution of 1-(2,2-dimethyl-propyl)-1H-pyrazole (51.1 g, 0.37 mol, CAS registry 725746-83-8) in DMF (100 mL) was added dropwise. Then it was heated to 100° C. overnight. After cooling, the reaction was quenched by slow addition of cold water, and it was neutralized with aqueous NaHCO3 solution and extracted with EtOAc. The combined organic layers were washed with brine, dried over MgSO4 and concentrated. The resulting residue was purified by column chromatograph on silicagel (petroleum ether-EtOAc 10:1) to give the title compound as light yellow oil: ESIMS [M+H]+=167; 1H NMR (400 MHz, DMSO-d6): δ 9.80 (s, 1H), 8.42 (s, 1H), 7.98 (s, 1H), 3.99 (s, 2H), 0.90 (s, 9H).

Provenance & Evidence