(9R)-9-acetyl-6,9,11-trihydroxy-8,10-dihydro-7H-tetracene-5,12-dione → 9(R)-bromoacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione
Reaction equation
[C:1]([C@:4]1([OH:26])[CH2:21][C:20]2[C:19]([OH:22])=[C:18]3[C:9]([C:10](=[O:24])[C:11]4[CH:12]=[CH:13][CH:14]=[CH:15][C:16]=4[C:17]3=[O:23])=[C:8]([OH:25])[C:7]=2[CH2:6][CH2:5]1)(=[O:3])[CH3:2].C1CNC(=O)C1.[Br:33][Br-]Br>O1CCCC1>[Br:33][CH2:2][C:1]([C@:4]1([OH:26])[CH2:21][C:20]2[C:19]([OH:22])=[C:18]3[C:9]([C:10](=[O:24])[C:11]4[CH:12]=[CH:13][CH:14]=[CH:15][C:16]=4[C:17]3=[O:23])=[C:8]([OH:25])[C:7]=2[CH2:6][CH2:5]1)=[O:3]Participants
3
Procedure
Reaction of 9(R)-acetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione ([α]D20 =-87° (c=0.1, CHCl3)) (11.5 g) with pyrrolidone hydrotribromide (18.19 g) was effected in tetrahydrofuran (1380 mg) at room temperature for 40 hours. After removing insoluble matters by filtration, the solvent was distilled off under reduced pressure to give 9(R)-bromoacetyl-6,9,11-trihydroxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione, which was used in the next step without purification.