反应详情

A solution of 2,2-dimethylpent-4-en-3-one (22.5 g) in anhydrous acetonitrile (50 cc) is added, at a maximum temperature of 5° C., to a suspension of triethylammonium pyrid-2-yldithiocarbamate (54.2 g) in anhydrous acetonitrile (150 cc). The reaction is allowed to proceed for 2 hours at between 5° and 20° C. The acetonitrile is evaporated off under reduced pressure (20 mmHg) at 45° C. The residue obtained is dissolved in methylene chloride (600 cc). The organic solution is washed four times with distilled water (total 600 cc), dried over sodium sulphate and evaporated. The product obtained (58.0 g) is dissolved in a mixture of chloroform (360 cc) and ethyl acetate (40 cc). The solution is chromatographed on a column of diameter 6 cm, containing silica (0.063-0.2 mm; 600 g). Elution is carried out with a mixture of chloroform (720 cc) and ethyl acetate (80 cc), this eluate being discarded, and then with a mixture of chloroform (3,000 cc) and ethyl acetate (350 cc), this eluate being collected and evaporated to dryness under reduced pressure (20 mmHg) at 45° C. The product obtained (42.0 g) is purified by recrystallisation from diisopropyl ether (200 cc). 4,4-Dimethyl-3-oxopentyl pyrid-2-yldithiocarbamate (36.0 g) (structure determined by IR spectroscopy in petroleum jelly), which melts at 95° C., is obtained.

1. customThe acetonitrile is evaporated off under reduced pressure (20 mmHg) at 45° C
2. customThe residue obtained
3. washThe organic solution is washed four times with distilled water (total 600 cc)
4. dry with materialdried over sodium sulphate
5. customevaporated
6. customThe product obtained (58.0 g)
7. customThe solution is chromatographed on a column of diameter 6 cm
8. additioncontaining silica (0.063-0.2 mm; 600 g)
9. washElution
10. additionis carried out with a mixture of chloroform (720 cc) and ethyl acetate (80 cc)
11. additionwith a mixture of chloroform (3,000 cc) and ethyl acetate (350 cc)
12. customthis eluate being collected
13. customevaporated to dryness under reduced pressure (20 mmHg) at 45° C
14. customThe product obtained (42.0 g)
15. customis purified by recrystallisation from diisopropyl ether (200 cc)