反应详情

The N-methylated product 63 (420 mg, 1.33 mmol) was dissolved in warm 2-ethoxyethanol (26 mL). To a refluxed solution of hydrazine monohydrate (1 mL, 31.9 mmol) and 2-ethoxyethanol (5 mL) under nitrogen was added prepared N-methylated product 62 solution dropwise over a 2 hr period and the solution continued to reflux for additional 1 hr. After cooling to room temperature, about half of the 2-ethoxyethanol was removed under reduced pressure and the remaining solution was refrigerated at −20° C. overnight. The precipitate was filtered and washed with 2-ethoxyethanol to give desired pyridazinone 64 (354 mg, 94%) as a white solid.

1. temperatureto reflux for additional 1 hr
2. customwas removed under reduced pressure
3. filtrationThe precipitate was filtered
4. washwashed with 2-ethoxyethanol