Electric Literature of 5334-39-4,Some common heterocyclic compound, 5334-39-4, name is 3-Methyl-4-nitro-1H-pyrazole, molecular formula is C4H5N3O2, 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 mixture of 6,7-dihydro-5H- pyrrolofl,2-a]imidazol-7-ol (1 g, 8.06 mmol) and 3-methyl-4-nitro-lH-pyrazole (1.13 g, 8.87 mmol) in THF (20 mL) was added PPh3 (3.17 g, 12.09 mmol) and then D1AD (2.44 g, 12.09 mmol, 2.4mL) dropwise at 0 C over a period of 30 min under N2. The mixture was warmed to 20 C and stirred for 12 h, then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (gradient PE:EtOAc from 10: 1 to 0: 1) to give the mixture of 7-(3-methyl-4-nitro-pyrazol-l-yl)-6,7-dihydro-5H-pyrrolo[l,2-a]imidazole and 7-(5-methyl- 4-nitro-lH-pyrazol-l -yl)-6,7-dihydro-5H-pyrrolo[l,2-a]imidazole as a white solid. LCMS: RT 0.112 min, m/z —— 234.1 [M + H .] To a solution of 7-(3- methyl-4-nitro-pyrazol-l-yl)-6,7-dihydro-5H-pyrrolo| l,2-a|imidazole and 7-(5-methyl-4-nitro-lH- pyrazol-l-yl)-6,7-dih}’dro-5H-pyrrolo[ l,2-a]imidazole (650 mg, 2.79 mmol) in MeOH (20 mL) was added Pd-C (10%, 0.3 g) under N2. The suspension was degassed under vacuum and purged with H2 several times. The mixture was stirred under H2 (15 psi) at 20 C for 4 h, then filteredand concentrated under reduced pressure, to give the mixture of l-(6,7-dihydro-5H-pyrrolo|T,2- a]imidazol-7-yl)-3-methyl-pyrazol-4-amine and l-(6,7-dihydro-5H-pyrrolo[ l,2-a]imidazol-7-yl)-5- methyl-lH-pyrazol-4-amine as a light yellow solid. LCMS: RT 0.62-0.878 min, m/z = 204.2 [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 3-Methyl-4-nitro-1H-pyrazole, its application will become more common.