Reference of 138786-86-4, These common heterocyclic compound, 138786-86-4, name is Methyl 4-nitro-1H-pyrazole-3-carboxylate, 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.
A mixture of methyl 4-nitro-1H-pyrazole-3-carboxylate obtained in Reference Example 18 (2.0 g, 11.7 mmol), methyl iodide (2.0 g, 14.0 mmol), potassium carbonate (1.62 g, 11.7 mmol) and acetone (60 mL) was stirred at 30C for 5 hr. The mixture was diluted with water, and extracted with chloroform. The extract was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (hexane-ethyl acetate 4:1 – 1:1) to give the title compound, methyl 1-methyl-4-nitro-1-pyrazole-3-carboxylate (Rf value 0.43) (0.95 g, yield 44%) and the title compound, methyl 1-methyl-4-nitro-1H-pyrazole-5-carboxylate (Rf value 0.71) (0.61 g, yield 28%). Methyl 1-methyl-4-nitro-1H-pyrazole-3-carboxylate 1H-NMR (CDCl3):delta 3.99(3H, s), 4.01(3H, s), 8.13(1H, s). Methyl 1-methyl-4-nitro-1H-pyrazole-5-carboxylate 1H-NMR (CDCl3):delta 4.02(3H, s), 4.03(3H, s), 8.01 (1H, s).
Statistics shows that Methyl 4-nitro-1H-pyrazole-3-carboxylate is playing an increasingly important role. we look forward to future research findings about 138786-86-4.