Extracurricular laboratory: Synthetic route of 3-Bromo-1,5-dimethyl-1H-pyrazole

The synthetic route of 5744-80-9 has been constantly updated, and we look forward to future research findings.

Synthetic Route of 5744-80-9, A common heterocyclic compound, 5744-80-9, name is 3-Bromo-1,5-dimethyl-1H-pyrazole, molecular formula is C5H7BrN2, 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.

Example 173 3-amino-5-(dicyclopropylmethyl)-7-(1,5-dimethyl-1H-pyrazol-3-yl)-1,5-dihydro-4H-pyrazolo[4,3-c]pyridin-4-one (0879) A mixture of 3-amino-7-bromo-5-(dicyclopropylmethyl)-1,5-dihydro-4H-pyrazolo[4,3-c]pyridin-4-one (300 mg) obtained in Example 78, Step C, 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi-1,3,2-dioxaborolane (283 mg), tetrakis(triphenylphosphine)palladium(0) (107 mg), potassium acetate (182 mg) and N,N-dimethylacetamide (4 mL) was stirred under an argon atmosphere at 110C for 4 hr. The reaction mixture was cooled to room temperature, 3-bromo-1,5-dimethyl-1H-pyrazole (195 mg), aqueous sodium carbonate solution (2 M, 0.928 mL) and tetrakis(triphenylphosphine)palladium(0) (107 mg) were added. Under an argon atmosphere, the reaction mixture was stirred at 130C for 5 hr. The reaction mixture was cooled to room temperature, water was added, and the mixture was extracted with ethyl acetate. The extract was washed with water and saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel chromatography (hexane/ethyl acetate) and further purified by silica gel chromatography (diol silica gel, hexane/ethyl acetate). The obtained solid was crystallized from ethyl acetate/diisopropyl ether to give the title compound (104 mg).

The synthetic route of 5744-80-9 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Takeda Pharmaceutical Company Limited; YOSHIDA, Masato; NAGAMIYA, Hiroyuki; OHBA, Yusuke; SETO, Masaki; YOGO, Takatoshi; SASAKI, Satoshi; TOKUNAGA, Norihito; ASO, Kazuyoshi; (298 pag.)EP2980089; (2016); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics