反应详情

In 600 ml of dioxane was suspended 30 g of 5-[4-[2-(5-ethyl-2-pyridyl) ethoxy]benzylidene]-2,4-thiazolidinedione obtained by substantially the same procedure as in Reference Example 4. To the suspension was added 20 g of 5% palladium-carbon (50% wet), which was subjected to catalytic reduction at 110° C. under elevated hydrogen pressure (100 kg/cm2) for 2 hours. The catalyst was filtered off when hot,and the filtrate was concentrated under reduced pressure to a volume of 540 ml. Precipitating crystals were collected by filtration and dissolved in 600 ml of dioxane when hot. The solution was cooled to room temperature slowly to cause recrystallization. The crystals were collected by filtration under reduced pressure and dried at 60° C. under reduced pressure to give 21.7 g of 5-[4-[2-(5-ethyl-2-pyridyl) ethoxy]benzyl]-2,4-thiazolidinedione. [The yield was 72% based on 5-[4-[2-(5-ethyl-2-pyridyl)ethoxy]benzylidene]-2,4-thiazolidinedione.]This product was in complete agreement with the authentic sample, 5-[4-[2-(5-ethyl-2-pyridyl)ethoxy]benzyl]-2,4-thiazolidinedione,-in various spectrum data.

1. customobtained by substantially the same procedure as in Reference Example 4
2. customwas subjected to catalytic reduction at 110° C. under elevated hydrogen
3. customfor 2 hours
4. filtrationThe catalyst was filtered off when
5. concentrationwas concentrated under reduced pressure to a volume of 540 ml
6. customPrecipitating crystals
7. filtrationwere collected by filtration
8. dissolutiondissolved in 600 ml of dioxane when hot
9. customrecrystallization
10. filtrationThe crystals were collected by filtration under reduced pressure
11. customdried at 60° C. under reduced pressure