Application of 2075-45-8, A common heterocyclic compound, 2075-45-8, name is 4-Bromo-1H-pyrazole, molecular formula is C3H3BrN2, its 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.
Step 3: Synthesis of 4-bromo-1-ethyl-1H-pyrazole (4) To a stirred solution of NaH (34.0 g, 0.85 mol; 60% in mineral oil) in THF (400 mL) was added a solution of 4-bromo-1H-pyrazole (50 g, 0.34 mol) in THF (100 mL) at 0 C. under inert atmosphere. The reaction mixture was warmed to RT and maintained at same temperature for 1 h. The reaction mixture was cooled again to 0 C. and added EtI (63.67 g, 0.408 mol) slowly for 5 min. The resultant solution was allowed to warm to RT and then stirred for 16 h. After completion of the reaction (monitored by TLC), the reaction mixture was quenched with ice-cold water (100 mL) and extracted with EtOAc (3*250 mL). The combined organic extracts were dried over Na2SO4, filtered and concentrated under reduced pressure to obtain the crude. The crude was purified (silica gel chromatography; 4-6% EtOAc/Hexanes) to afford compound 4 (43 g, 72%) as a pale yellow liquid. 1H NMR (500 MHz, CDCl3): delta 7.45 (s, 1H), 7.41 (s, 1H), 4.15 (q, J=7.5 Hz, 2H), 1.47 (t, J=7.5 Hz, 3H); MS (ESI): m/z 175.0 (M+H+).
The synthetic route of 2075-45-8 has been constantly updated, and we look forward to future research findings.