Related Products of 5334-40-7, These common heterocyclic compound, 5334-40-7, name is 4-Nitro-1H-pyrazole-3-carboxylic acid, 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.
Stage 4: Synthesis of 4-nitro-lH-pyrazole-3-carboxylic acid methyl ester; A 2OL reaction vessel equipped with a digital thermometer and stirrer was charged with 4- nitro-lH-pyrazole-3-carboxylic acid (1.117Kg, 7.11mol, lwt) and methanol (8.950L, 8vol). The reaction mixture was stirred under nitrogen, cooled to 0 to 50C, thionyl chloride (0.581L, 8.0mol, 0.52vol) added over 180 minutes and the resultant mixture allowed to warm to and stir at 18 to 22C overnight after which time 1H NMR analysis (d6-DMSO) indicated reaction completion. The reaction mixture was concentrated under reduced pressure at 40 to 450C, the residue treated with toluene and re-concentrated (3x 2.250L, 3x 2vol) under reduced pressure at 40 to 45C to give 4-nitro-lH-pyrazole-3-carboxylic acid methyl ester as an off-white solid (1.210Kg, 99.5%th).; Stage 4: Preparation of 4-nitro-lH-pyrazole-3-carboxylic acid methyl; esterC4H3N3O4 C5H5N3O4FW: 157.09 FW: 171.114-Nitro-lH-pyrazole-3-carboxylic acid (1.00kg, 6.37mol, l.Owt) and methanol (8.00L, 8.0vol) were charged to a flange flask equipped with a mechanical stirrer, condenser and thermometer. The suspension was cooled to 0 to 5C under nitrogen and thionyl chloride (0.52L, 7.12mol, 0.52vol) was added at this temperature. The mixture was warmed to 15 to 25C over 16 to 24 hours. Reaction completion was determined by 1H NMR analysis (dbeta-DMSO). The mixture was concentrated under vacuum at 35 to 45C. Toluene (2.00L, 2.0vol) was charged to the residue and removed under vacuum at 35 to 45C. The azeotrope was repeated twice using toluene (2.00L, 2.0vol) to give 4-nitro-lH-pyrazole-3-carboxylic acid methyl ester (1.071Kg, 98.3%) as an off white solid.
Statistics shows that 4-Nitro-1H-pyrazole-3-carboxylic acid is playing an increasingly important role. we look forward to future research findings about 5334-40-7.