Uses
3,6-Diethynylcarbazole is an organic intermediate that can be prepared from 3,6-dibromocarbazole as a raw material, followed by the removal of the trimethylsilyl group to obtain 3,6-diethynylcarbazole.
Synthesis
In a flame-dried 100 mL round-bottomed Schlenk flask, 3,6-dibromocarbazole (1.0 g, 3.07 mmol) and 2 mL of trimethylmethylsilylacetylene were dissolved in 40 mL of freshly distilled dry triethylamine. A mixture of 100 mg [(PPh3)2PdCl2] (0.14 mmol), 20 mg triphenylphosphine (0.07 mmol), and 20 mg CuI (0.1 mmol) was added and the suspension was stirred and refluxed for 12 hours under a nitrogen atmosphere. After removing the volatile solvent, the product was extracted with 100 mL of dichloromethane. The solvent was removed under reduced pressure to obtain 3,6-bis[trimethylsilyl ethynyl]carbazole as an off-white solid in 98% yield.Anal.Calcd for C22H25NSi2(2):C,73.48;H,7.01;N,3.89.Found:C,73.38;H,7.15;N,3.58. 1HNMR(CDCl3,400MHz):δ8.96(s,NH),8.18(s,2H,),7.55(d,2H,J=8.4Hz),7.34(d,2H,J=8.0Hz),0.32(s,18H).IR(KBr):ν2138.8cm-1for the ethynyl group.
