反应详情

A mixture of 4-(4-fluorophenyl)-5-methyl-1,2,3-thiadiazole (6.19 g), N-bromosuccinimide (12.4 g), 2,2′-azobis(isobutyronitrile) (100 mg) and carbon tetrachloride (100 ml) was stirred for 6 hrs. with heating under reflux. The reaction mixture was washed with water, dried over anhydrous magnesium sulfate and concentrated. Sodium acetate (30 g) and acetic acid (100 ml) were added to the residue and the mixture was stirred for 12 hrs. with heating under reflux. 6N Hydrochloric acid (50 ml) was added and the mixture was further stirred for 1 hr. with heating under reflux. The reaction mixture was concentrated, poured into a saturated aqueous sodium hydrogen carbonate solution and extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to silica gel column chromatography to give 4-(4-fluorophenyl)-1,2,3-thiadiazole-5-carbaldehyde (360 mg, yield 5.4%) as pale-yellow crystals from a fraction eluted with hexane-ethyl acetate (2:1, v/v).

1. temperaturewith heating
2. temperatureunder reflux
3. washThe reaction mixture was washed with water
4. dry with materialdried over anhydrous magnesium sulfate
5. concentrationconcentrated
6. additionSodium acetate (30 g) and acetic acid (100 ml) were added to the residue
7. stirringthe mixture was stirred for 12 hrs
8. temperaturewith heating
9. temperatureunder reflux
10. addition6N Hydrochloric acid (50 ml) was added
11. stirringthe mixture was further stirred for 1 hr
12. temperaturewith heating
13. temperatureunder reflux
14. concentrationThe reaction mixture was concentrated
15. additionpoured into a saturated aqueous sodium hydrogen carbonate solution
16. extractionextracted with ethyl acetate
17. washThe organic layer was washed with saturated brine
18. dry with materialdried over anhydrous magnesium sulfate
19. concentrationconcentrated