Acetone → Justicidin A

Participants

Reaction Steps

The product of step F, diphyllin, (10; 75 mg; 0.197 mmol), and 1 ml methyl iodide were dissolved in 5 ml acetone containing 82 mg potassium carbonate (0.6 mmol), and the resulting solution heated at about 60° for one hour. After removing acetone, a residue remained which was treated with methylene chloride and 10% aqueous hydrogen chloride. After separation of aqueous and organic layers, the organic layer was washed with saturated sodium chloride and dried over magnesium sulfate. Evaporation of solvent and purification on a preparative thin-layer chromatography plate provided ca. 67 mg of 9-(1,3-benzodioxol-5-yl)-4,6,7-trimethoxynaphtho[2,3-c]furan-1-(3H)-one, 11, mp 248°-250°. IR(CHCl3): 1770, 1620 cm-1 ; PMR (CDCl3): δ7.39 (s, 1H), 6.91 (s, 1H), 6.83-6.64 (m, 3H), 5.94 (2s, 2H), 5.42 (s, 2H), 4.05 (s, 3H), 3.98 (s, 3H), and 3.73 (s, 3H); MS: m/z 394.1006 (M+), calcd. for C22H18O7, 394.1049. A separate sample of product 11, prepared by substantially the foregoing procedure, was recrystallized from chloroform-ether, mp 256°-258°. This crystalline product was again recrystallized from chloroform-ether, mp 258°-260°.

Provenance & Evidence