反应详情

A solution of 3.3 parts of 1-(2,3-dihydro-2,2-dimethyl-4H-1-benzopyran-4-yl)-1H-imidazole-5-carboxylic acid in 45 parts in warm N,N-dimethylformamide was cooled to room temperature and then 2 parts of 1,1'-carbonylbis[1H-imidazole] were added. The whole was stirred at room temperature till CO2 evolution had ceased (±30 minutes). The mixture was heated to ±70° C. and 2.4 parts of ethanol and 0.1 parts of sodium ethoxide were added. Stirring was continued over weekend at ±70° C. After evaporation, the residue was taken up in water and trichloromethane. The organic layer was washed with water, dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using trichloromethane as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from hexane. The product was filtered off and dried, yielding 2.36 parts (63.5%) of ethyl 1-(2,3-dihydro-2,2-dimethyl-4H-1-benzopyran-4-yl)-1H-imidazole-5-carboxylate; mp. 80.9° C. (compound 1.138).

1. custom(±30 minutes)
2. temperatureThe mixture was heated
3. customto ±70° C.
4. waitwas continued over weekend at ±70° C
5. customAfter evaporation
6. washThe organic layer was washed with water
7. customdried
8. filtrationfiltered
9. customevaporated
10. customThe residue was purified by column chromatography over silica gel
11. customThe pure fractions were collected
12. customthe eluent was evaporated
13. customThe residue was crystallized from hexane
14. filtrationThe product was filtered off
15. customdried