Water → HCID 22933413, compound

Temperature

0 °C

Under a nitrogen atmosphere, a solution of tetrafluoroborate nitrite (110 mg, 0.783 mmol) in acetonitrile (3 ml) was added dropwise to a suspension of the 1H-indazol-5-ol (100 mg, 0.745 mmol) obtained in Reference Example 4 in acetonitrile (4.0 ml) at −35° C. over a period of 10 minutes, and the resulting mixture was slowly heated to 0° C. After 2 hours, the reaction solution was poured into water and extracted with ethyl acetate. The extract solution was concentrated under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate). The residue purified was concentrated under reduced pressure and the resulting residue was washed with ethanol/diisopropyl ether by repulping to obtain 4-nitro-1H-indazol-5-ol (59.8 mg, 45%).

1. extractionextracted with ethyl acetate
2. concentrationThe extract solution was concentrated under reduced pressure
3. customthe resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate)
4. customThe residue purified
5. concentrationwas concentrated under reduced pressure
6. washthe resulting residue was washed with ethanol/diisopropyl ether

ORD record

ord-0ff4aa82ce834a76b7abcc79b338b388

Source dataset

uspto-grants-2007_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07199147B2