meta-Substituted triphenylamines as new dyes displaying exceptionally large Stokes shifts

Selection of Bis-Indolyl Pyridines and Triphenylamines as New Inhibitors of SARS-CoV-2 Cellular Entry by Modulating the Spike Protein/ACE2 Interfaces

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the infectious agent that has caused the current coronavirus disease (COVID) pandemic. Viral infection relies on the viral S (spike) protein/cellular receptor ACE2 interaction. Disrupting this interaction would lead to early blockage of viral replication. To identify chemical tools to further study these functional interfaces, 139,146 compounds from different chemical libraries were screened through an S/ACE2 in silico virtual molecular model. The best compounds were selected for further characterization using both cellular and biochemical approaches, reiterating SARS-CoV-2 entry and the S/ACE2 interaction. We report here two selected hits, bis-indolyl pyridine AB-00011778 and triphenylamine AB-00047476. Both of these compounds can block the infectivity of lentiviral vectors pseudotyped with the SARS-CoV-2 S protein as well as wild-type and circulating variant SARS-CoV-2 strains in various human cell lines, including pulmonary cells naturally susceptible to infection. AlphaLISA and biolayer interferometry confirmed a direct inhibitory effect of these drugs on the S/ACE2 association. A specific study of the AB-00011778 inhibitory properties showed that this drug inhibits viral replication with a 50% effective concentration (EC50) between 0.1 and 0.5 μM depending on the cell lines. Molecular docking calculations of the interaction parameters of the molecules within the S/ACE2 complex from both wild-type and circulating variants of the virus showed that the molecules may target multiple sites within the S/ACE2 interface. Our work indicates that AB-00011778 constitutes a good tool for modulating this interface and a strong lead compound for further therapeutic purposes.

Novel thieno-[3,4-b]-pyrazines cored dendrimers with carbazole dendrons: design, synthesis, and application in solution-processed red organic light-emitting diodes

A series of novel red-emitting thieno-[3,4-b]-pyrazine-cored molecules containing oligo-carbazole dendrons (called C1-TP, C2-TP) are synthesized. Their photophysical, electrochemical, and electroluminescent properties are investigated. The peripheral carbazolyl units facilitate the hole transporting ability and inhibit the intermolecular interactions, but quench the fluorescence of the thieno-[3,4-b]-pyrazine core through Intramolecular Charge Transfer (ICT). Introduction of a polyphenyl spacer between the core and the first generation carbazole dendrons, i.e., C-DTP, decreases the ICT efficiency. In addition to providing the site-isolation effect on the planar emissive core, these bulky dendrons enable these molecules to be solution processable. As a result, efficient OLEDs with saturated red emission are fabricated by spin coating technique using these dendritic materials as nondoped emitting layer. C-DTP exhibits much better device performance than C1-TP and C2-TP, while the small molecular reference compound containing neither the spacer nor the carbazole dendrons (TP) fails to transmit pure red emission under identical conditions. A brightness of 925 cd m(-2) and a luminous efficiency of 0.53 cd A(-1) are obtained for C-DTP, which are comparable with OLEDs fabricated from thieno-[3,4-b]-pyrazine-based counterparts by the vacuum deposition method or those assembled with other red fluorescent dendrimers via the solution processing method.