m-Chloroperbenzoic acid → HCID 53879492, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 2.6 g (6.56 mmol) of 1-(4-bromo-2,6-dimethylphenyl)-3-ethyl-5-methylthio-1H-pyrazole4-carboxylic acid ethyl ester in 50 mL of THF in a 125 mL 3-neck RBF was stirred under N2 and cooled to 170° C. Then 0.826 9 (9.80 mmol) of anhydrous sodium bicarbonate was added followed by a solution of 6.79 g (19.6 mmol) of m-chloroperbenzoic acid dissolved in 40 mL of THF. During the addition, the temperature of the reaction mixture was not allowed to rise above 20° C. After 1 hour, an aliquot workup showed that the reaction mixture consisted of about 34% of the desired sulfone and about 66% of the intermediate sulfoxide and after stirring overnight at room temperature, the conversion to sulfone was complete. A solution of 50 mL of 20% sodium bisulfite was then added and the resulting reaction mixture was stirred for 15 minutes. The reaction mixture was diluted with 50 mL of water and the product was extracted into 100 mL of CH2Cl2. The organic extracts were washed twice with saturated bicarbonate solution and once with 20% sodium bisulfite solution. The organic layer was dried over sodium sulfate and evaporated to give the desired product (2.91 g) as a gum. 1H-NMR (CDCl3) δ 0.28 (3H,t,J=7), 1.42 (3H, t, J=7), 1.97 (6H, s), 2.93 (2H, q, J=7), 3.39 (3H, s), 4.42 (2H, q, J=7), 7.29 (2H, s).

Provenance & Evidence