10.1016/S0040-4039(01)80782-6
The research focuses on the synthesis of dinucleoside phosphorodithioates and phosphorothioates, which are analogues of oligonucleotides with potential applications as antiviral agents and in studies involving interactions with nucleic acids and proteins. The purpose of the study is to develop an alternative and convenient approach to synthesizing these analogues using protected nucleoside 3'-phosphonodithioates as starting materials. The researchers successfully converted 5'-O-(9-phenylxanthen-9-yl)thymidine into its 3'-phosphonodithioate derivative and further into dinucleoside phosphonothioate and dinucleoside phosphorodithioate with good overall yields. Key chemicals used in the process include triethylammonium salt, 3'-O-acetylthymidine, pivaloyl chloride, and sulfur. The study concludes that the procedure is potentially applicable to the synthesis of phosphorodithioate analogues of oligodeoxyribo- and oligoribo-nucleotides, both in solution and on solid supports, and that the synthesized dinucleoside phosphorodithioate (6a) is resistant to digestion by snake venom phosphodiesterase, bovine spleen phosphodiesterase, and nuclease PI.
10.1021/ol991376o
The research presents a method for the large-scale synthesis of stereodefined oligo(nucleoside 3',5'-methanephosphonates) (oligo-PMe), which are potential candidates for drugs in antisense and antigene strategies due to their sequence-specific recognition, nuclease resistance, and ability to access intracellular environments. The study focuses on developing a strategy to synthesize diastereomerically pure oligo-PMe through transient 3'-O protection, allowing the conversion of a chirally defined methanephosphonanilidate group into diastereomerically pure "oligomeric building blocks" for stereospecific coupling. 3'-O-acetylthymidine is used as a reactant in the condensation reaction with compound 2 to form the dinucleoside methanephosphonate (4). It provides the thymidine nucleoside unit necessary for the elongation of the oligonucleotide chain. Trichloroacetic acid is used to selectively remove the 5'-O protective group from the methanephosphonanilidate, yielding the corresponding 5'-OH compound. This step is crucial for the subsequent coupling reactions.
10.1002/asia.201100467
The research aims to develop and characterize a series of spirobifluorene-based bipolar compounds (D2ACN, DNPACN, DNTACN, and DCzACN) for use as host materials in highly efficient phosphorescent organic light-emitting diodes (PhOLEDs). The study focuses on tailoring the morphological stability, triplet energy, bipolar charge-transport behavior, and HOMO/LUMO energy levels of these compounds by varying the structural features of the donor (D) and acceptor (A) branches. 1-Naphthylphenylamine was used in the palladium-catalyzed C-N bond formation to synthesize DNPACN. Tris(2-phenylpyridinato)iridium(III) is used as a green phosphorescent dopant in electrophosphorescent devices. The researchers fabricated multilayer PhOLED devices using these bipolar hosts and achieved high efficiencies, with one device incorporating D2ACN and the red emitter [Os(bpftz)2(PPhMe2)2] exhibiting saturated red electrophosphorescence with CIE coordinates (0.65, 0.35) and remarkable efficiencies of 20.3% (21 cd/A) and 13.5 lm/W at a brightness of 1000 cd/m2. The study concludes that these spiro-configured bipolar compounds, with their balanced electron and hole mobilities, are highly suitable as host materials for high-efficiency PhOLEDs, demonstrating significant potential for both red and green phosphorescent devices.
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