Ethanol → 1H-Indazol-1-amine

Temperature

55 °C

To a solution of 2.2 g(55 mmol) of sodium hydroxide in 30 ml of water was added 1.33 g(10 mmol) of 1H-indazole and ethanol was slowly added at 50° C. until the reaction mixture was dissolved thoroughly. The resulting mixture was heated to 55° C. and 2.83 g(25 mmol) of hydroxylamine-O-sulfonic acid was slowly added over 30 min with vigorous stirring followed by further stirring for 30 min. After completion of reaction, the resulting precipitate was filtered off, and the filtrate was extracted with dichloromethane(30 ml×2), dried over anhydrous magnesium sulfate and concetrated under the reduced pressure. The concentrate was chromatographed over silica gel using 10% ethyl acetate/dichloromethane as an eluent. The fractions containing the desired product were concentrated under the reduced pressure and crystallized from benzene/petroleum ether to give 0.63 g of the desired compound(47%).

1. additionwas slowly added at 50° C. until the reaction mixture
2. dissolutionwas dissolved thoroughly
3. stirringby further stirring for 30 min
4. customAfter completion of reaction
5. filtrationthe resulting precipitate was filtered off
6. extractionthe filtrate was extracted with dichloromethane(30 ml×2)
7. dry with materialdried over anhydrous magnesium sulfate
8. customThe concentrate was chromatographed over silica gel using 10% ethyl acetate/dichloromethane as an eluent
9. additionThe fractions containing the desired product
10. concentrationwere concentrated under the reduced pressure
11. customcrystallized from benzene/petroleum ether

ORD record

ord-f1c9aeae49db4adcbbaba347376e4625

Source dataset

uspto-grants-1994_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05336673