Synthesis
The general procedure for the synthesis of 1-(N,N-dimethyl-sulfonyl)pyrazole from pyrazole and N,N-dimethylaminosulfonyl chloride is as follows:
Example 80: Synthesis of 2-amino-1-(4-chlorophenyl)-1-[4-(3-ethyl-1H-pyrazol-4-yl)phenyl]ethanol
Step 80A: Preparation of pyrazole-1-sulfonic acid dimethylamide
To a solution of pyrazole (4.8 g, 81.9 mmol) in acetonitrile (125 mL) was sequentially added 1,4-diazabicyclo[2.2.2]octane (DABCO, 10.1 g, 90.3 mmol) and N,N-dimethanaminosulfonyl chloride (8.8 mL, 82.9 mmol). The reaction mixture was stirred at room temperature for 18 hours. Upon completion of the reaction, the reaction solution was concentrated in vacuum and the residue was partitioned with water and ethyl acetate. The organic layer was separated, washed sequentially with 2N hydrochloric acid and saturated brine, and dried over anhydrous magnesium sulfate. The organic layer was concentrated under reduced pressure to afford 1-(N,N-dimethyl-sulfonyl)pyrazole as a colorless oil (13.1 g, 91% yield).
LC/MS (PS-A2) retention time 2.16 min, [M+H]+ 176.
References
[1] Synthesis, 2006, # 5, p. 793 - 798
[2] Chemistry - An Asian Journal, 2015, vol. 10, # 8, p. 1626 - 1630
[3] Advanced Synthesis and Catalysis, 2014, vol. 356, # 7, p. 1555 - 1561
[4] Patent: WO2006/136830, 2006, A1. Location in patent: Page/Page column 190-191
[5] Patent: WO2006/136829, 2006, A2. Location in patent: Page/Page column 129
