反应详情

To a stirred and cooled (0° C.) solution of 40 parts of ethyl 6-amino-3,4-dihydro-2H-1-benzopyran-2-carboxylate, 86 parts of pyridine and 234 parts of methylbenzene was added dropwise a solution of 20.6 parts of methanesulfonyl chloride in 135 parts of methylbenzene. Upon completion, stirring was continued overnight at room temperature. The reaction mixture was evaporated and the oily residue was taken up in water. The product was extracted with dichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol, saturated with ammonia, (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 210 parts of 2,2'-oxybispropane and 12 parts of acetonitrile, yielding 10.2 parts (18.9%) of ethyl 3,4-dihydro-6-[(methylsulfonyl)amino]-2H-1-benzopyran-2-carboxylate; mp. 111.1° C. (intermediate 25).

1. stirringUpon completion, stirring
2. customThe reaction mixture was evaporated
3. extractionThe product was extracted with dichloromethane
4. customThe extract was dried
5. filtrationfiltered
6. customevaporated
7. customThe residue was purified by column chromatography over silica gel using
8. additiona mixture of trichloromethane and methanol
9. customThe pure fractions were collected
10. customthe eluent was evaporated
11. customThe residue was crystallized from a mixture of 210 parts of 2,2'-oxybispropane and 12 parts of acetonitrile