反应详情

A mixture comprising 523 mg of 2-ethyl-4,5-dichloro-6-hydroxy-3(2H)pyridazinone prepared in Reference Example 1, 1.71 g of 3-n-propoxy-4-methoxybenzylamine, 15 ml of 1,4-dioxane and 15 ml of water, was refluxed under stirring for 24 hours, and 1.71 g of 3-n-propoxy-4-methoxybenzylamine was further added thereto, and the reaction was conducted under the same condition for 2 days. The solvent was distilled off under reduced pressure, and dilute hydrochloric acid was added to the residue thereby obtained. The mixture was extracted with ethyl acetate. The extract was washed with water and a saturated sodium chloride aqueous solution in this order, and dried over sodium sulfate. Then, the solvent was distilled off to obtain a yellow oily substance. The oily substance was purified by silica gel column chromatography, and the slightly yellow oily substance obtained by eluting with a solvent mixture of benzene-ethyl acetate (1:2 v/v) was crystallized from ethyl acetate-diethyl ether, to obtain 418 mg of the above identified compound having a melting point of from 73° to 74° C. as colorless crystals.

1. temperaturewas refluxed
2. waitthe reaction was conducted under the same condition for 2 days
3. distillationThe solvent was distilled off under reduced pressure, and dilute hydrochloric acid
4. additionwas added to the residue
5. customthereby obtained
6. extractionThe mixture was extracted with ethyl acetate
7. washThe extract was washed with water
8. dry with materiala saturated sodium chloride aqueous solution in this order, and dried over sodium sulfate
9. distillationThen, the solvent was distilled off
10. customto obtain a yellow oily substance
11. customThe oily substance was purified by silica gel column chromatography
12. customthe slightly yellow oily substance obtained
13. washby eluting with a solvent mixture of benzene-ethyl acetate (1:2 v/v)
14. customwas crystallized from ethyl acetate-diethyl ether
15. customto obtain 418 mg of the
16. customof from 73° to 74° C.