Asymmetric Design of Bipolar Host Materials with Novel 1,2,4-Oxadiazole Unit in Blue Phosphorescent Device
摘要:
The intrinsic asymmetry of 1,2,4-oxadiazole was utilized to synthesize three isomers, DCzmOXD-1, DCzmOXD-2, and mCzmOXD, and high triplet energies over 2.80 eV made them good candidates for host materials in blue OLEDs. The best efficiencies of 23.0 cd A(-1)/20.5 lm W1-/11.2% in CE/PE/EQE were achieved by DCzmOXD-1 with derivation at the beta-carbon position of 1,2,4-oxadiazole.
Various 3,5-disubstituted-1,2,4-oxadiazoles are smoothly formed via copper-catalyzed cascade annulation of amidines and methylarenes. This tandem oxidation-amination-cyclization transformation represents a straightforward protocol to prepare 1,2,4-oxadiazoles from easily available starting materials, with...
Orthogonal aerobic conversion of N-benzyl amidoximes to 1,2,4-oxadiazoles or quinazolinones
作者:Feng-Lian Zhang、Yi-Feng Wang、Shunsuke Chiba
DOI:10.1039/c3ob41393d
日期:——
Concise synthesis of 1,2,4-oxadiazoles was achieved by heating N-benzyl amidoximes with K3PO4 in DMF at 60 °C under an O2 atmosphere via benzylic C–H oxygenation. On the other hand, aerobic treatment of N-benzyl amidoximes with Cs2CO3 in DMSO at 100 °C could result in oxidative skeletal rearrangement to deliver quinazolinones as a major product. This orthogonal product selectivity could be realized by difference of the reaction temperature as well as selection of the solvents and inorganic bases.
Synthesis of 1,2,4-oxadiazoles utilizing ethyl 2-cyano-2-(2-nitrophenylsulfonyloxyimino) acetate (ortho-nosylOXY) as a catalyst and dehydrating reagent under microwave irradiation