Methanol → HCID 178499180, compound

Temperature

2.5 °C

A 20 L reaction vessel equipped with a digital thermometer and stirrer was charged with 4-nitro-1H-pyrazole-3-carboxylic acid (1.117 Kg, 7.1 μmol, 1 wt) and methanol (8.950 L, 8 vol). The reaction mixture was stirred under nitrogen, cooled to 0 to 5° C., thionyl chloride (0.581 L, 8.0 mol, 0.52 vol) added over 180 minutes and the resultant mixture allowed to warm to and stir at 18 to 22° C. overnight after which time 1H NMR analysis (d6-DMSO) indicated reaction completion. The reaction mixture was concentrated under reduced pressure at 40 to 45° C., the residue treated with toluene and re-concentrated (3×2.250 L, 3×2 vol) under reduced pressure at 40 to 45° C. to give 4-nitro-1H-pyrazole-3-carboxylic acid methyl ester as an off-white solid (1.210 Kg, 99.5% th).

1. customA 20 L reaction vessel
2. customequipped with a digital thermometer and stirrer
3. temperatureto warm to and
4. stirringstir at 18 to 22° C. overnight after which time 1H NMR analysis (d6-DMSO)
5. customreaction completion
6. concentrationThe reaction mixture was concentrated under reduced pressure at 40 to 45° C.
7. additionthe residue treated with toluene
8. concentrationre-concentrated (3×2.250 L, 3×2 vol) under reduced pressure at 40 to 45° C.

ORD record

ord-dd49295b3e544382aa6d12d4833c2687

Source dataset

uspto-grants-2012_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08110573B2