Hydrochloric Acid → 6,13-Ethanopentacenedione, 6,13-dihydro-

Participants

Reaction Conditions

Reaction Steps

A reaction vessel was purged with nitrogen, and then charged with dimethylsulfoxide (8.6 ml, 93.5 mmol) and methylene chloride (48 ml). Once the reaction vessel was cooled to −60° C., the mixture was added with anhydrous trifluoroacetic acid (11.7 ml, 84.3 mmol), and the resultant solution was stirred for 10 minutes. After stirring, a solution of the 6,13-dihydro-15,16-dihydroxy-6,13-ethanopentacene (0.96 g, 2.7 mmol) obtained in Step 2 dissolved in dimethyl sulfoxide (4 ml) was slowly added dropwise into the reaction solution. After the dropwise addition, stirring was performed for 1.5 hours while maintaining the temperature at −60° C., and then the resultant solution was added with triethylamine (27.5 ml). Then, stirring was further performed for 1.5 hours, after which the temperature was returned to room temperature. The reaction solution was poured into 10% hydrochloric acid (150 ml) and was extracted with methylene chloride. The resultant organic layer was washed with water and saturated saline, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The obtained crude product was washed with ethyl acetate to give the intended 6,13-dihydro-6,13-ethanopentacene-15,16-dione (0.45 g, 50%)

Provenance & Evidence