反应详情

A solution of 900 mg (5.02 mmol) of 1-(2-amino-5-hydroxyphenyl)-2-methyl-1-propanone in 30 ml of half-conc. hydrochloric acid is treated slowly at −5° C. with a solution of 364 mg (5.27 mmol) of sodium nitrite in 15 ml of water and, after addition is complete, stirred at this temperature for 30 min. A solution of 2.266 g (10.04 mmol) of tin(II) chloride dihydrate in 15 ml of conc. hydrochloric acid is then added dropwise to the reaction mixture at −5° C. and the reaction is slowly warmed to room temperature. The mixture is neutralized using 45% strength sodium hydroxide solution, filtered off through kieselguhr, washed with ethyl acetate, and the organic phase is dried over sodium sulphate, concentrated in vacuo and dried. 370 mg (36%) of 5-hydroxy-3-isopropyl-1H-indazole are obtained.

1. additionafter addition
2. filtrationfiltered off through kieselguhr
3. washwashed with ethyl acetate
4. dry with materialthe organic phase is dried over sodium sulphate
5. concentrationconcentrated in vacuo
6. customdried