Water → 1-(2-chlorobenzyl)-3,5-dimethyl-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

Powdered potassium hydroxide (1.751 g, 31.2 mmol) was added to a solution of 3,5-dimethylpyrazole (2 g, 20.81 mmol) in anhydrous DMSO (10.40 ml) and the resulting heterogeneous solution was stirred for 1.5 hr at 80° C. before being cooled to room temperature. 2-Chloro benzylchloride (2.64 ml, 20.81 mmol) was then added in 6 M DMSO over 15 min, and the solution was stirred for a further 1.5 hrs. Upon completion as observed by TLC, the reaction was poured over water and the resulting aqueous phase was extracted with two 20 mL portions of CHCl3. The combined organic layers were washed with 100 mL of water, dried with anhydrous MgSO4 and concentrated under reduced pressure to yield 4.55 g (99%) of 1-(2-chlorobenzyl)-3,5-dimethyl-1H-pyrazole as a clear liquid. 1H NMR (300 MHz, CDCl3) δ 7.41-7.31 (m, 1H), 7.24-7.09 (m, 2H), 6.59-6.50 (m, 1H), 5.90 (s, 1H), 5.31 (s, 2H), 2.26 (s, 3H), 2.15 (s, 3H). 13C NMR (75 MHz, CDCl3) δ 148.32, 139.96, 135.46, 131.96, 129.42, 128.76, 127.72, 127.48, 105.84, 50.12, 13.80, 11.15. HRMS (m/z): [MNa]+ calc for C12H13ClN2Na+243.07. found 243.0651.

Provenance & Evidence