反应详情

2.00 g of crude methyl 3-hydroxyiminomethyl-4-methylsulfonyl-2-methylbenzoate was dissolved in 35 ml of chloroform Chlorine gas was blown into the resulting solution, with stirring, for 30 minutes at -13~0° C. The solution was further stirred for 30 minutes at 0° C. Nitrogen gas was blown into the reaction solution to remove excessive chlorine. Chloroform was concentrated under reduced pressure to give a solid product. The obtained solid was dissolved in 50 ml of ether. Acetylene gas was blown in, with stirring, for 5 minutes at -11° C. Then 1.64 g of triethylamine dissolved in 5 ml of ether was added dropwise at -15~13.5° C. Further acetylene gas was blown in for 20 minutes at -15~13.5° C. The resulting reaction mixture was transferred to a 50 ml, stainless-steel autoclave, which was cooled beforehand, and stirred for 3.5 hours at 60~70° C. The reaction solution was cooled down, poured into water, and extracted with ethyl acetate. The organic layer was washed with water, then with a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. The solvent was distilled out under reduced pressure. The obtained residue was purified by column chromatography on silica gel with benzene/ethyl acetate=9/1 to give 0. 82 g of the title compound as white crystals. m.p. 87~89° C.

1. stirringThe solution was further stirred for 30 minutes at 0° C
2. customto remove excessive chlorine
3. concentrationChloroform was concentrated under reduced pressure
4. customto give a solid product
5. stirringwith stirring, for 5 minutes at -11° C
6. additionwas added dropwise at -15~13.5° C
7. customwas blown in for 20 minutes at -15~13.5° C
8. customThe resulting reaction mixture
9. stirringstirred for 3.5 hours at 60~70° C
10. temperatureThe reaction solution was cooled down
11. extractionextracted with ethyl acetate
12. washThe organic layer was washed with water
13. dry with materialwith a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate
14. distillationThe solvent was distilled out under reduced pressure
15. customThe obtained residue was purified by column chromatography on silica gel with benzene/ethyl acetate=9/1
16. customto give 0