Methanol → HCID 178499180, compound

Temperature

2.5 °C

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.

1. customequipped with a mechanical stirrer, condenser
2. temperatureThe mixture was warmed to 15 to 25° C. over 16 to 24 hours
3. customReaction completion
4. concentrationThe mixture was concentrated under vacuum at 35 to 45° C
5. additionToluene (2.00 L, 2.0 vol) was charged to the residue
6. customremoved under vacuum at 35 to 45° C

ORD record

ord-55f30cfd6bf7422ab03c9e39b9c8324d

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08435970B2