Synthetic Route of 2075-45-8,Some common heterocyclic compound, 2075-45-8, name is 4-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.
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.
Reference:
Patent; PHARMAKEA, INC.; Evans, Jillian Frances; US9051320; (2015); B1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics