Reference of 16034-46-1,Some common heterocyclic compound, 16034-46-1, name is 1-Methyl-1H-pyrazole-5-carboxylic acid, molecular formula is C5H6N2O2, 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.
To a solution of 1-methyl-1H-pyrazole-5-carboxylic acid (compound 4A, 4.07 g, 32.2 mmol), DIEA (12.2 g, 94.1 mmol) in CH2Cl2 (30 mL) was added EDCI (10.3 g, 53.7 mmol) and DMAP (3.94 g, 32.2 mmol) at -5 C., the mixture was stirred at -5 C. for 30 min under N2. Then 4-bromo-2-methylaniline (compound 7, 5.00 g, 26.9 mmol) was added, the mixture was stirred at -5 C. for 30 min, then warmed to 25 C., stirred for 11 hrs. TLC (petroleum ether:ethyl acetate=1:1, Rf=0.27) showed one new point formed. The mixture was concentrated in vacuum to give light yellow oil. The oil was purified by silica gel column chromatography (petroleum ether: ethyl acetate=80:20 to 50:50) to give N-(4-bromo-2-methylphenyl)-1-methyl-1H-pyrazole-5-carboxamide (compound 8, 6.40 g, 81% yield) as light yellow solid. 1H NMR (400 MHz, CDCl3) delta delta ppm 7.72 (d, J=8.2 Hz, 1H), 7.47-7.58 (m, 2H), 7.33-7.41 (m, 2H), 6.64 (s, 1H), 4.20 (s, 3H), 2.28 (s, 3H); ES-LCMS m/z 294.1 [M+H]+.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 1-Methyl-1H-pyrazole-5-carboxylic acid, its application will become more common.
Reference:
Patent; Kyn Therapeutics; Castro, Alfredo C.; Evans, Catherine Anne; (108 pag.)US2019/55218; (2019); A1;,
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