反应详情

A mixture of 5.5 g of the above prepared 2-(3-pyridyl)-1,3,4-oxadiazole, 8.5 g of phosphorus pentasulfide and 70 ml of xylene is stirred for 16 hours at 150°-160° C. To the cooled reaction mixture are added 50 ml of water and stirring is continued for another 5 minutes. The reaction mixture is then filtered. The filter residue is taken up in 100 ml of 10% sodium hydroxide solution. After extraction with chloroform, the organic phase is washed with water, dried and concentrated. After purification by column chromatography over silica gel with a 95:5 mixture of chloroform/ethanol as eluant, the crude 2-(3-pyridyl)-1,3,4-thiadiazole (compound 1) of the formula ##STR8## with a melting point of 64°-67° C., is obtained.

1. additionA mixture of 5.5 g of the
2. customTo the cooled reaction mixture
3. stirringstirring
4. waitis continued for another 5 minutes
5. filtrationThe reaction mixture is then filtered
6. extractionAfter extraction with chloroform
7. washthe organic phase is washed with water
8. customdried
9. concentrationconcentrated
10. customAfter purification by column chromatography over silica gel
11. additionwith a 95:5 mixture of chloroform/ethanol as eluant