Sodium Carbonate → (2S,4aS,6aR,7R,9S,10aS,10bR)-9-(hydroxy)-2-(3-furanyl)dodecahydro-6a,10b-dimethyl-4,10-dioxo-2H-naphtho[2,1-c]pyran-7-carboxylic acid methyl ester
Reaction equation
CC([O:4][C@@H:5]1[C:19](=[O:20])[C@H:18]2[C@@:8]([CH3:27])([CH2:9][CH2:10][C@@H:11]3[C@:17]2([CH3:21])[CH2:16][C@@H:15]([C:22]2[CH:23]=[CH:24][O:25][CH:26]=2)[O:14][C:12]3=[O:13])[C@H:7]([C:28]([O:30][CH3:31])=[O:29])[CH2:6]1)=O.C([O-])([O-])=O.[Na+].[Na+]>CO>[CH3:31][O:30][C:28]([C@@H:7]1[CH2:6][C@H:5]([OH:4])[C:19](=[O:20])[C@H:18]2[C@@:8]1([CH3:27])[CH2:9][CH2:10][C@H:11]1[C@:17]2([CH3:21])[CH2:16][C@@H:15]([C:22]2[CH:23]=[CH:24][O:25][CH:26]=2)[O:14][C:12]1=[O:13])=[O:29]Participants
4
Procedure
A mixture of 1 (3.5 g, 8.0 mmol) and Na2CO3 (3.4 g, 32.2 mmol) in absolute MeOH (150 mL) was stirred at room temperature for 4 b. The solvent was removed under reduced pressure and CH2Cl2 (500 mL) was added to the crude residue. The organic extract was washed successively with 2N HCl (50 mL) and saturated NaCl (50 mL) and dried (Na2SO4). The solvent was removed under reduced pressure and MeOH (100 mL) was added to the residue. The resulting solid was collected by filtration and dried to afford 2.4 g (77%) of 8a as a white solid, mp 211-214° C. (Lit. 213-216° C.).