反应详情

3.6 g of powdered potassium hydroxide are added to a solution, cooled to 0° C., of 15 g of the 2-(4-chlorophenyl)-5-(pyrid-3-yl)-4,5-dihydro-1,3,4-thiadiazole prepared according to Example 1a) in 80 ml of acetone. After stirring for ca. 5 minutes at 0°-5° C., 6.9 g of iodine are added in portions and the exothermic reaction is kept at about 0°-5° C. by cooling with ice. The batch is subsequently stirred for 4 hours at ca. 0° C. The precipitated product is isolated by filtration and washed with a small amount of acetone. The crude product is taken up in a 1:3 mixture of tetrahyrofuran/ethyl acetate and the solution is washed once with water and twice with a saturated solution of sodium chloride, dried over sodium sulfate and concentrated by evaporation. The title compound of formula ##STR20## so obtained has a melting point of 143°-145° C. (compound 21).

1. customprepared
2. customthe exothermic reaction
3. customis kept at about 0°-5° C.
4. temperatureby cooling with ice
5. stirringThe batch is subsequently stirred for 4 hours at ca. 0° C
6. customThe precipitated product is isolated by filtration
7. washwashed with a small amount of acetone
8. additionThe crude product is taken up in a 1:3 mixture of tetrahyrofuran/ethyl acetate
9. washthe solution is washed once with water and twice with a saturated solution of sodium chloride
10. dry with materialdried over sodium sulfate
11. concentrationconcentrated by evaporation