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

HRID 238121Notes

Reaction equation

[OH-].[K+].[CH3:3][C:4]1[CH:8]=[C:7]([CH3:9])[NH:6][N:5]=1.[Cl:10][C:11]1[CH:18]=[CH:17][CH:16]=[CH:15][C:12]=1[CH2:13]Cl.O>CS(C)=O>[Cl:10][C:11]1[CH:18]=[CH:17][CH:16]=[CH:15][C:12]=1[CH2:13][N:5]1[C:4]([CH3:3])=[CH:8][C:7]([CH3:9])=[N:6]1

Participants

Conditions

Temperature: 80 °C

Procedure

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.

Workup

temperaturebefore being cooled to room temperature
stirringthe solution was stirred for a further 1.5 hrs
extractionthe resulting aqueous phase was extracted with two 20 mL portions of CHCl3
washThe combined organic layers were washed with 100 mL of water
dry with materialdried with anhydrous MgSO4
concentrationconcentrated under reduced pressure

Sources & evidence

ORD record: ord-ab4372ff7d8a4d6e927411694a832348
Source dataset: uspto-grants-2014_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08642614B2

Reaction notes

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