Toluene → Phenanthrene

Participants

Reaction Steps

A degassed, efficiently stirred suspension of 37.2 g (200 mmol) of 4-methylnaphtalene-1-boronic acid, 18.0 g (50 mmol) of 2,7-dibromo-9,10-dimethylphenanthrene and 52.2 g (210 mmol) of potassium phosphate 1-hydrate in a mixture of 75 ml of dioxane, 150 ml of toluene and 200 ml of water was admixed with 457 mg (1.5 mmol) of tri-o-tolylphosphine and then with 56 mg (0.25 mmol) of palladium(II) acetate. After heating under reflux for 16 h and cooling the reaction mixture, the precipitated solid was filtered off with suction and washed three times with 100 ml each time of water and three times with 100 ml each time of ethanol. After drying under reduced pressure (1 mbar, 80° C., 16 h), the product was extracted in a Soxhlett extractor with chloroform through a glass fibre extraction sleeve (pore size 0.5 μm) in order to remove palladium traces. The product which remained after concentration of the chloroform was recrystallized three times from chlorobenzene (approx. 25 ml/g) and three times from DMF (approx. 60 ml/g), and subsequently sublimed twice under high vacuum (p=5×10−5 mbar, T=320-330° C.). The yield at a purity of 99.9% by HPLC was 15.6 g (32 mmol), corresponding to 64.2% of theory.

Provenance & Evidence