반응 #551194

반응 방정식

9(R)-acetoxyacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione

bromine

cyclohexene oxide

HBr

→

7-bromo-9(S)-acetoxyacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione

용매

carbon tetrachloride

chloroform

반응 조건

후처리

1. 1
   온도with heating for 3 hours, while the reaction mixture
2. 2
   기타The solvent was removed under reduced pressure and ether (52.5 ml)
3. 3
   workup.ADDITIONwas added to the residue
4. 4
   기타precipitated crystals
5. 5
   여과were filtered

실험 절차

Treatment of 9(R)-acetoxyacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione (3.5 g) with bromine (3.41 g) was effected in a refluxing mixture of chloroform (875 ml) and carbon tetrachloride (1750 ml) with heating for 3 hours, while the reaction mixture was irradiated with 500 W lamp as radical reaction initiator in the presence of cyclohexene oxide (2.51 g) as a scavenger of the generated HBr. The solvent was removed under reduced pressure and ether (52.5 ml) was added to the residue. The resultant mixture was stirred at room temperature for 1.5 hours and precipitated crystals were filtered to give reddish orange powders of 7-bromo-9(S)-acetoxyacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione. M.P., 173°-175° C.

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