Efficient Synthesis of 2,2'-Dicarbazole-1,1'-Biphenyl - Prospective Host Material for PHOLEDs
1
Ural Federal University, 620002, Russia, Yekaterinburg, Mira St, 19,
2 I.Ya. Postovsky Institute of Organic Synthesis (Ural Division of the Russian Academy of Sciences), 620000, Russia, Yekaterinburg, S.Kovalevskoi St, 20-22
* Author to whom correspondence should be addressed.
2 I.Ya. Postovsky Institute of Organic Synthesis (Ural Division of the Russian Academy of Sciences), 620000, Russia, Yekaterinburg, S.Kovalevskoi St, 20-22
* Author to whom correspondence should be addressed.
2,2'-Dicarbazole-1,1'-diphenyl (2,2'-CBP) is a prospective host material for phosphorescent light emmiting diodes (PHOLED)s. The synthesis of 2,2'-CBP is limited by the availability of starting materials. We wish to report an efficient protocol for the synthesis of 2,2'-CBP with overal yield about 90% starting from o-nitrobenzoic acid. Thus, Pd catalized homocoupling of o-nitrobenzoic acid affords 2,2'-dinitro-1,1'-diphenyl (2,2'-DNDP) in 95% yield. Pd catalized reduction of 2,2'-DNDP and the following double arylation of 2,2'-diaminodiphenyl with 2,2'-dibromo-1,1'-diphenyl (which can be obtained from 2,2'-diamino-1,1'-diphenyl in 70-76% yield) affords the final product in 95% yield with overal yield after 3 steps of 90 %.
Keywords: 2,2'-CBP, Pd coupling, PHOLEDs
