Synthetic Route of 2075-45-8, These common heterocyclic compound, 2075-45-8, name is 4-Bromo-1H-pyrazole, 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.
1-{[2-(trimethylsilyl)ethoxy]methyl}-1H pyrazole-4-carbaldehyde was prepared as follows: To a solution of 4-bromo pyrazole (16.90 g, 115 mmol) in THF (400 mL) under N2 at 0 C was added NaH ( 3.31 g, 138 mmol) and stirred for 15 min. Neat SEM-Cl (21.10 g, 126.46 mmol) was added drop wise to the reaction mixture and stirred overnight at rt. The reaction was quenched with water (200 mL) and excess THF was removed in vacuo. The residue was extracted with EtOAc (2×500 mL), dried over MgS04 and removed in vacuo to give crude 4- bromo- 1 – ( [2-(trimethylsilyl)ethoxy]methyl) – lH-pyrazole (36 g) as a yellow oil. The crude material was used in next step without further purification. To a solution of 4-bromo-l-{[2-(trimethylsilyl)ethoxy]methyl}-IH-pyrazole (35.83 g, 129.35 mmol) in THF (750 mL) at at -78 C under N2 was added n-BuLi (67.26 mL, 168.16 mmol, 2.5 M) slowly. After the reaction mixture was stirred for 3 h at -78 C, DMF (50 mL) was added at -78 C and warmed to rt overnight. It was cooled to -30 C, quenched with 1 N HCl (120 mL) and stirred at 0 C for 30 min and 30 min at rt. The extraction was carried out with EtOAc (2×500 mL) and washed with brine (2×150 mL). The combined organic layers were dried over MgS04, filtered and removed in vacuo. The crude material was purified on silica gel and eluted with EtOAc/hexanes (from 5% to 20%) to yield 1-{[2- (trimethylsilyl)ethoxy]methyl]-1H pyrazole-4-carbaldehyde (12.34 g, 34%) as brown oil
The synthetic route of 2075-45-8 has been constantly updated, and we look forward to future research findings.