p-Toluenesulfonic acid → 3-(2,5-dimethyl-1H-pyrrol-1-yl)-1-methyl-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

A solution of 1-methyl-1H-pyrazol-3-ylamine (0.92 g, 9.5 mmol) in benzene (4.8 mL) was treated with hexane-2,5-dione (1.34 mL, 11.4 mmol) and para-toluenesulfonic acid (182 mg, 0.95 mmol) and was heated to 115° C. under Dean-Stark conditions for 4 h. After this time, the reaction was cooled to 25° C., concentrated in vacuo and dried under high vacuum overnight. The resulting residue was dissolved in methylene chloride (100 mL) and was washed with water (1×150 mL), dried over sodium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (ISCO, 80 g, 1:4 ethyl acetate/hexanes) afforded 3-(2,5-dimethyl-pyrrol-1-yl)-1-methyl-1H-pyrazole (1.57 g, 94%) as a green oil; ES+-HRMS m/e calcd for C10H13N3 [M+H+] 176.1182, found 176.1182.

Provenance & Evidence