A common heterocyclic compound, 5334-40-7, name is 4-Nitro-1H-pyrazole-3-carboxylic acid, molecular formula is C4H3N3O4, 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. 5334-40-7.
Preparation of 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester 4-Nitro-1H-pyrazole-3-carboxylic acid (1.00 kg, 6.37 mol, 1.0 wt) and methanol (8.00 L, 8.0 vol) were charged to a flange flask equipped with a mechanical stirrer, condenser and thermometer. The suspension was cooled to 0 to 5 C. under nitrogen and thionyl chloride (0.52 L, 7.12 mol, 0.52 vol) was added at this temperature. The mixture was warmed to 15 to 25 C. over 16 to 24 hours. Reaction completion was determined by 1H NMR analysis (d6-DMSO). The mixture was concentrated under vacuum at 35 to 45 C. Toluene (2.00 L, 2.0 vol) was charged to the residue and removed under vacuum at 35 to 45 C. The azeotrope was repeated twice using toluene (2.00 L, 2.0 vol) to give 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester (1.071 Kg, 98.3%) as an off white solid.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 4-Nitro-1H-pyrazole-3-carboxylic acid, its application will become more common.