邻甲基苯胺制备苯并吡唑

邻甲基苯胺制备苯并吡唑，胺基经重氮化在醋酸钾催化下与邻位甲基关环。

Procedure：To a solution of the example 34 (40 mg, 66.82 mmol, 1 eq) in chloroform (1 mL) was added acetic acid (12.04 mg, 200.45 mmol, 11.46 ml, 3 eq), and the resulting mixture was stirred at 0°C for 1 hour, and then potassium acetate(1.97 mg, 20.04 mmol, 0.3 eq) and isoamyl nitrite (15.65 mg, 133.63 mmol, 17.99 ml, 2 eq) were added to the above reaction  solution. The  above mixture  was stirred at 0°C  for  0.5 hour,  and  then  stirred at 25°C  for 1.4  hours.  TLC (dichloromethane : methanol = 12 : 1) showed that the reaction of the raw materials was complete, and LCMS detected the MS of the target compound. The reaction solution was quenched with saturated aqueous sodium bicarbonate solution (25 mL), and then extracted with ethyl acetate (10 mL*3). The combined organic phase was washed with saturated brine(10 mL*2), dried over anhydrous sodium sulfate and then concentrated. The resulting residue was purified by preparative

TLC (dichloromethane : methanol = 12 : 1), and the resulting crude product was further purified by preparative HPLC(formic acid) to obtain example 37. 1H NMR (400 MHz, CD3OD) δ 7.77 (s, 1H), 7.65 (d, J = 8.0 Hz, 1H), 7.44 (d, J = 8.8Hz, 1H), 7.26 (s, 1H), 6.84 (dd, J = 16.8, 10.8 Hz, 1H), 6.29 (dd, J = 16.8, 2.0 Hz, 1H), 5.83 (dd, J= 10.8, 2.0 Hz, 1H),4.63 (br s, 4H), 4.42-4.29 (m, 2H), 4.14 (dd, J = 5.2, 9.6 Hz, 2H), 3.90-3.847(m, 9H), 2.77 (q, J = 7.2 Hz, 4H), 2.20 (s, 3H), 1.13 (t, J = 7.2 Hz, 6H); LCMS (ESI) m/z: 610.4 (M+1).

文献：EP3741756