反应详情

温度

50 °C

5-Acetamido-2,4,6-triiodo-N,N'-bis(2,3-dihydroxypropyl)isophthalamide (37.4 g; 50 mmole) was dissolved in propylene glycol (110 ml) by adding 5.3 M sodium methoxide (14.2 ml; 75 mmole) and heating in an oil bath at 50° C. When all or nearly all of the starting material was dissolved, the excess of methanol was evaporated in vacuo. After cooling to room temperature 3-chloropropane-1,2-diol (6.3 ml; 75 mmole) was added. When the reaction mixture was applied to TLC in system (B) after stirring for two days, two new spots with Rf values 0.26 and 0.33 in a ratio of about 1:9 and less than 0.5% of the starting material with Rf 0.42 were observed. The new spots were assumed to represent endo/exo isomers. The reaction mixture was evaporated in vacuo and the residue dissolved in methanol (125 ml). A small amount of undissolved material was filtered off and water (30 ml) added. This solution was treated with a mixture of Amberlite cation exchange resin IR 120H (27.5 g) and Dowex anion exchange resin 1×4 (50 g) for two hours. After filtration, the pH of the solution was adjusted to 4.9, and then evaporated in vacuo. The oily residue was triturated in butanol (125 ml). The product crystallized out following this treatment. After storing at -20° C., the product was filtered off. Then the product was dissolved in water, and the solution evaporated in vacuo. Yield 38 g.

1. dissolutionWhen all or nearly all of the starting material was dissolved
2. customthe excess of methanol was evaporated in vacuo
3. additionwas added
4. customThe reaction mixture was evaporated in vacuo
5. dissolutionthe residue dissolved in methanol (125 ml)
6. filtrationA small amount of undissolved material was filtered off
7. additionwater (30 ml) added
8. additionThis solution was treated with a mixture of Amberlite cation exchange resin IR 120H (27.5 g) and Dowex anion exchange resin 1×4 (50 g) for two hours
9. filtrationAfter filtration
10. customevaporated in vacuo
11. customThe oily residue was triturated in butanol (125 ml)
12. customThe product crystallized out
13. customAfter storing at -20° C.
14. filtrationthe product was filtered off
15. dissolutionThen the product was dissolved in water
16. customthe solution evaporated in vacuo