Electric Literature of 14521-80-3,Some common heterocyclic compound, 14521-80-3, name is 3-Bromo-1H-pyrazole, molecular formula is C3H3BrN2, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
23a 3-Bromo-l-(4-nitrophenyl)-l /-pyrazole 23a: Sodium hydride (60% w/w in mineral oil, 41 mg, 1.02 mmol, 1.5 equiv) was carefully added in portions to a stirred solution of 22a (100 mg, 0.68 mmol, 1.0 equiv) in THF (6.8 mL) at 0 C. After 20 min, 1-fluoro -4 -nitrobenzene 22c (0.08 mL, 0.75 mmol, 1.1 equiv) was added dropwise, and the reaction mixture was set to reflux at 60 C. Upon consumption of the starting material as indicated by TLC, the reaction mixture was cooled to 25 C, quenched with a saturated solution of aqueous ammonium chloride (1.2 mL), and the two phases were separated. The aqueous layer was extracted with ethyl acetate (3 x 5 mL), and the combined organic layers were dried with anhydrous magnesium sulfate and concentrated in vacuo. The crude residue obtained was purified by flash column chromatography (silica gel, 20% ethyl acetate in hexanes) to afford -arylpyrazole 23a (144 mg, 0.54 mmol, 79%) as a white solid. 23a: Rf = 0.30 (silica gel, 20% ethyl acetate in hexanes); FT-IR (neat) v 3144, 1595, 1516, 1407, 1359, 1335, 1200, 1176, 1112, 1042, 955, 937, 852, 749, 732, 684 cm 1; NMR (600 MHz, CDC13) delta = 8.33 (d, J = 9.2 Hz, 2 H), 7.93 (d, J = 2.6 Hz, 1 H), 7.84 (d, J = 9.2 Hz, 2 H), 6.58 (d, J = 2.6 Hz, lH) ppm; 13C NMR (151 MHz, CDC13) delta = 145.9, 143.7, 130.7, 129.0, 125.6, 118.6, 112.6 ppm; HRMS (ESI) calcd for C9H6BrN302 [M+H]+ 267.9716 found 267.9711.
The synthetic route of 14521-80-3 has been constantly updated, and we look forward to future research findings.