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温度

0 °C

A solution of ethylene glycol (55 ml) in tetrahydrofuran (200 ml) was treated at around 0° C. (ice bath cooling) with sodium hydride (60% dispersion in oil, 5.9 g) over 40 minutes. After the addition was complete, 3,4,6-trichloropyridazine (27 g) containing isomers of bromo-dichloropyridazine as impurity was added portionwise and washed in with more dry THF (50 ml) and the mixture was stirred at 0° C. for 1 hour and then at room temperature overnight. The mixture was concentrated (to ⅓ volume) then diluted with aqueous sodium bicarbonate solution and extracted with chloroform (5×) and ethyl acetate (3×). The combined organic extracts were washed with water, dried over sodium sulphate and evaporated and the solids filtered off and washed with CHCl3 (×3) and dried in a vacuum oven overnight at 40° C. affording a white solid (25.5 g, 83%), containing some bromo-derivative (10-15%).

1. additionAfter the addition
2. additionwas added portionwise
3. washwashed in with more dry THF (50 ml)
4. customat room temperature
5. customovernight
6. concentrationThe mixture was concentrated (to ⅓ volume)
7. additionthen diluted with aqueous sodium bicarbonate solution
8. extractionextracted with chloroform (5×) and ethyl acetate (3×)
9. washThe combined organic extracts were washed with water
10. dry with materialdried over sodium sulphate
11. customevaporated
12. filtrationthe solids filtered off
13. washwashed with CHCl3 (×3)
14. customdried in a vacuum oven overnight at 40° C.