反应详情

A mixture of 1-(2,6-dimethylpyrazolo[5,1-b][1,3]thiazol-7-yl)ethanone (655 mg, 3.37 mmol) and a 5N aqueous solution of hydrochloric acid (14.2 mL) was cooled to 0° C., and an aqueous (1.0 mL) solution of sodium nitrite (465 mg, 6.74 mmol) was added. This reaction mixture was stirred at room temperature over one day and night. To the mixture was added a 5N aqueous solution of sodium hydroxide at 0° C. to make the solution basic, and produced blue solid was filtered and washed with a small amount of water. The obtained blue solid was dissolved in a 2N aqueous solution of hydrochloric acid (13.5 mL), zinc powder (220 mg, 3.37 mmol) was added to the mixture, and the mixture was stirred at room temperature for 15 minutes. To the mixture, zinc powder (220 mg, 3.37 mmol) was added again, and the mixture was stirred at room temperature for 1.5 hours. The insoluble matters were filtered off and then a 5N aqueous solution of sodium hydroxide was added to the filtrate at 0° C. to neutralize the mixture. A substance of interest was extracted with ethyl acetate, and the organic layer was washed with brine, and dried over magnesium sulfate. The mixture was filtered to yield a filtrate, the solvent was distilled off under reduced pressure, and the obtained solid was dried to obtain the title compound (306 mg, 1.83 mmol).

1. customproduced blue solid
2. filtrationwas filtered
3. washwashed with a small amount of water
4. additionwas added to the mixture
5. stirringthe mixture was stirred at room temperature for 15 minutes
6. stirringthe mixture was stirred at room temperature for 1.5 hours
7. filtrationThe insoluble matters were filtered off
8. additiona 5N aqueous solution of sodium hydroxide was added to the filtrate at 0° C.
9. extractionA substance of interest was extracted with ethyl acetate
10. washthe organic layer was washed with brine
11. dry with materialdried over magnesium sulfate
12. filtrationThe mixture was filtered
13. customto yield a filtrate
14. distillationthe solvent was distilled off under reduced pressure
15. customthe obtained solid was dried