Potassium Acetate → methyl 1H-indazole-4-carboxylate

A mixture of methyl 3-amino-o-toluate (100 g, 605 mmol), a solution of ammonium tetrafluoroborate (83.0 g, 787 mmol) in water (600 mL) and concentrated hydrochloric acid (121 mL, 3.93 mmol) was cooled to 0° C., and a solution of sodium nitrite (41.8 g, 605 mmol) in water (88 mL) was added dropwise to the mixture over 25 min. This mixture was stirred for 35 min, and the resulting solid was collected by filtration. This solid was washed with water, methanol and diethyl ether, dried under nitrogen atmosphere, and added to a solution of potassium acetate (65.4 g, 666 mmol) and 18-crown-6 (4.50 g, 17.0 mmol) in chloroform (1.37 L). The resulting mixture was stirred at room temperature for 2 hr, and water (700 mL) was added. The partitioned organic layer was washed with water, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was triturated with hexane, and collected by filtration to give the title compound (63.0 g, yield 59%).

1. filtrationthe resulting solid was collected by filtration
2. washThis solid was washed with water, methanol and diethyl ether
3. customdried under nitrogen atmosphere
4. stirringThe resulting mixture was stirred at room temperature for 2 hr
5. washThe partitioned organic layer was washed with water
6. dry with materialdried over anhydrous magnesium sulfate
7. customthe solvent was evaporated under reduced pressure
8. customThe residue was triturated with hexane
9. filtrationcollected by filtration

ORD record

ord-d3dc41a2ca944671967f0a15fb479d82

Source dataset

uspto-grants-2012_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08110585B2