Water → HCID 12766836, compound

Participants

Reaction Steps

The product of the principal reaction of example VII (compound VI) has added thereto ice (3 g) and there is added thereto a chromic acid solution of (4 ml.) from a previously prepared solution comprising chromium trioxide (24 g.), concentrated sulfuric acid 30 g, and water to 100 ml. The chromic acid solution is added dropwise with agitation while holding the mixture at 0° C. Thirty minutes after reaction is complete the reaction mixture is removed from the cooling bath and permitted to warm to ambient temperature at which it remains for 2 hours. The reaction mixture is then diluted with distilled water (20 ml.) and extracted with ethyl acetate (20 ml.). The aqueous phase is further extracted with ethyl acetate (20 ml.) and the organic phases iare combined. To the organic phase is added zinc dust (1 g) and the mixture shaken briefly, the zinc dust is removed by filtration and the organic filtrate washed successively with dilute aqueous hydrochloric acid (3 N. 20 ml.) saturated aqueous sodium bicarbonate (20 ml.) and distilled water (20 ml.) The organic extract is dried over anhydrous magnesium sulfate, filtered, and the solvent removed from the filtrate by evaporation under reduced pressure to yield an orange residue which was taken up in methylene-chloride/ethylacetate (17:3, 20 ml.) and passed through a silica gel column: (20 g). The solvent is removed from the eluate under reduced pressure and the residue recrystallized (from aqueous methanol) to give 9,9-Bis(ethoxycarbonyl-4,6,11-trimethoxy-7,8,9,10-tetrahydronaphthacene-5,-12-quinone (VII) (860 mg., 0.017 moles 62%) as yellow needle crystals m.p. 123°-125° C.

Provenance & Evidence