Some common heterocyclic compound, 13808-64-5, name is 4-Bromo-3-methylpyrazole, molecular formula is C4H5BrN2, 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. Computed Properties of C4H5BrN2
10330] To a suspension of NaH 60% in oil (0.3 g; 7.45 mmol) in tetrahydrofuran (150 mE) there is added, at 100 C., 4-bromo-3-methyl-1H-pyrazole dissolved in 15 mE of tetrahydrofuran dropwise, over 15 minutes. Afier stirring for 40 minutes at ambient temperature, iodomethane (0.45 mE; 7.45 mmol) is added dropwise, and then the reaction mixture is stirred overnight. Afier adding water, the reaction mixture is evaporated and taken up in dichloromethane. The organic phase is separated off and dried over Mg504, filtered and concentrated to dryness. The residue is purified by chromatography over silica gel to yield a mixture of the title compounds (4-bromo-1 ,3-dimethyl-pyrazole and 4-bromo-1 ,5- dimethyl-pyrazole respectively in a ratio of 4:6).4-bromo-1 ,5-dimethyl-1H-pyrazole10331] ?H NMR (500 MHz, dmso-d6) oe ppm: 7.41 (s, 1H),3.76 (s, 3H), 2.22 (s, 3H)4-bromo-1 ,3-dimethyl-1H-pyrazole10332] ?H NMR (500 MHz, dmso-d6) oe ppm: 7.81 (s, 1H),3.74 (s, 3H), 2.09 (s, 3H)
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 13808-64-5, its application will become more common.
Reference:
Patent; LE TIRAN, Arnaud; LE DIGUARHER, Thierry; STARCK, Jerome-Benoit; HENLIN, Jean-Michel; GUILLOUZIC, Anne-Francoise; DE NANTEUIL, Guillaume; GENESTE, Olivier; FEJES, Imre; TATAI, Janos; NYERGES, Miklos; DAVIDSON, James Edward Paul; MURRAY, James Brooke; CHEN, I-Jen; DURAND, Didier; US2015/31673; (2015); A1;,
Pyrazole – Wikipedia,
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