反应详情

温度

10 °C

A mixture of 53 g. of the product of Example 9 in dry chloroform was prepared. The mixture was cooled to 10° C., and 75 g. of boron tribromide were added. The mixture was stirred for 24 hours at room temperature. The mixture then was poured into water, the chloroform layer was separated, and the aqueous layer was extracted with additional chloroform which was added to the separated chloroform layer. The resulting chloroform mixture then was filtered, and the filtrate was concentrated to dryness. The residue was dissolved in benzene, the benzene solution was filtered, concentrated to dryness, and the residue was chromatographed on silica using 10 percent ether in benzene as eluant. Those fractions containing material having the same Rf value were combined and rechromatographed on alumina using ether as solvent followed by a mixture of 10 percent methanol in ether. The title compound (5.8 g.) was obtained, melting point 138°-140° C.

1. additionA mixture of 53 g
2. customthe chloroform layer was separated
3. extractionthe aqueous layer was extracted with additional chloroform which
4. additionwas added to the separated chloroform layer
5. filtrationThe resulting chloroform mixture then was filtered
6. concentrationthe filtrate was concentrated to dryness
7. dissolutionThe residue was dissolved in benzene
8. filtrationthe benzene solution was filtered
9. concentrationconcentrated to dryness
10. customthe residue was chromatographed on silica using 10 percent ether in benzene as eluant
11. additionThose fractions containing material
12. customrechromatographed on alumina
13. additionfollowed by a mixture of 10 percent methanol in ether