Carbazole → 4,4'-Bis(9H-carbazol-9-yl)biphenyl

Participants

Reaction Conditions

Reaction Steps

4,4′-Diiodobiphenyl (10.001 g, 24.63 mmol), carbazole (9.078 g, 54.29 mmol), K2CO3 (20.087 g, 145.34 mmol), 18-crown-6 (0.100 g, 0.34 mmol), and copper powder (10.051 g, 158.16 mmol) were combined in reaction flask. To the flask, o-dichlorobenzene (50 mL) was added. The reaction was heated under inert N2 atmosphere at 180° C. overnight. TLC showed evidence of limited di-substitution product which necessitated the addition of K2CO3 (4.994 g, 36.13 mmol) and Cu powder (5.223 g, 82.19 mmol) to the reaction flask to promote di-substitution. The reaction was allowed to proceed overnight. Additional reagents had no noticeable effect on the reaction so the reaction was stopped. Insoluble material was removed by vacuum filtration and washed with several portions of THF. On standing, a crystalline product crashed out of the filtrate. Further crystallization was promoted by the addition of a large amount of methanol. The precipitate was vacuum filtered to isolate. TLC (hexanes: DCM=8:2) confirmed precipitate was product with minor impurity. Purification was accomplished by dissolving the precipitate in hot boiling THF followed by filtration to obtain a green insoluble impurity. The product began to precipitate on standing and cooling. The filtrate/product mixture was dried under vacuum until the product started crashing out of solution and methanol was added to promote full precipitation. The product was isolated by vacuum filtration and air dried (24 hours). A cream colored flaky product was obtained (7.660 g, 64.2%).

Provenance & Evidence