Water → 3-chloro-1-methyl-1H-pyrazole-5-carboxylic acid

To a solution of methyl 3-chloro-1-methyl-1H-pyrazole-5-carboxylate (6.0 g, 34.4 mmol) in dioxane (10 ml) was added H2O (10 ml) and LiOH (1.65 g, 68.7 mmol). After stirring for 16 h, the reaction mixture was washed with CH2Cl2 and then the aqueous phase acidified by drop wise addition of conc. HCl. The resulting residue was filtered off, washed with water and dried to yield the title compound (5.0 g, 91%). [1H-NMR (DMSO-d6, 360 MHz) δ 13.77 (br. s, 1H), 6.88 (d, 1H), 4.05 (s, 3H); HPLC-MS RtJ=0.47 min; [M+H]+=160.9, 163.0]

1. washthe reaction mixture was washed with CH2Cl2
2. additionthe aqueous phase acidified by drop wise addition of conc. HCl
3. filtrationThe resulting residue was filtered off
4. washwashed with water
5. customdried

ORD record

ord-183ac1dfd9d94eadbac3b6ccbdf198fd

Source dataset

uspto-grants-2014_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08742106B2