反应详情

10.0 g (66 millimoles) of 2,3-dihydro-3-oxo-1,2-benzisothiazole were suspended in 140 ml of dimethylformamide, and 2.0 g (66 millimoles) of 80% strength sodium hydride were added a little at a time, while stirring thoroughly. After 15 minutes, 12.8 g (80 millimoles) of 3-bromo-2-methyl-3-cyanoprop-1-ene were slowly added dropwise, and the reaction mixture was stirred for 2 hours at 80° C. and then cooled. The solvent was distilled off under reduced pressure, the mixture was taken up in ice-water and extracted with methylene chloride, and the organic phase was washed thoroughly with H2O, dried and evaporated down. The crude product (16 g of a dark oil) was then purified by column chromatography (silica gel, mobile phase 95:5 mixture of methylene chloride and methanol). 3.5 g (23%) of 3-(2,3-dihydro-3-oxo-1,2-benzisothiazol-2-yl)-1-cyano-2-methylprop-1-ene of melting point 128°-130° C. were obtained.

1. stirringthe reaction mixture was stirred for 2 hours at 80° C.
2. temperaturecooled
3. distillationThe solvent was distilled off under reduced pressure
4. extractionextracted with methylene chloride
5. washthe organic phase was washed thoroughly with H2O
6. customdried
7. customevaporated down
8. customThe crude product (16 g of a dark oil) was then purified by column chromatography (silica gel, mobile phase 95:5 mixture of methylene chloride and methanol)