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Driven by the success of quinoidal units for enabling high‐performance polymer semiconductors, herein a new quinoidal building block that terminated by indandione is reported. By introducing Br atoms into the terminal benzene rings of indandione, two CPs, P2TbTI‐DPP and P2TbTI‐TIID, are synthesized through Stille polycondensation. The strong electron‐withdrawing ability of indandione‐terminated quinoidal unit enables P2TbTI‐DPP and P2TbTI‐TIID with low‐lying LUMO energy levels of ≈–3.90 eV. Organic thin‐film transistors based on P2TbTI‐DPP and P2TbTI‐TIID exhibit n‐type transport behavior. Besides, it is found that the electron mobility of these two polymers is weakly dependent on the annealing temperature due to the near‐amorphous of polymer thin‐film. [ABSTRACT FROM AUTHOR]

In this work, we synthesized a series of chalcone‐based 2‐arylidene‐1,3‐indandione and evaluated their inhibitory activities against the mushroom tyrosinase enzyme. Based on benzylidene moiety, derivatives were divided into 4‐benzyloxy‐benzylidene and 4‐benzyloxy‐3‐methoxy‐benzylidene derivatives. Among them, 2‐(3‐methoxy‐4‐((4‐methylbenzyl)oxy)benzylidene)‐1H‐indene‐1,3(2H)‐dione (6 l) was presented the superior activity with an IC50 value of 15.85±3.64 μM, which was lower than the standard kojic acid. The kinetic study of compound 6 l displayed an uncompetitive inhibition mode on the tyrosinase enzyme. Next, the docking study exhibited compound 6 l formed hydrogen bonds and hydrophobic interactions with critical highly conserved amino acids in the target protein. Furthermore, based on the molecular dynamics simulation, compound 6 l depicted noticeable interaction with the essential residues of the binding site and exhibited a stable complex during the simulation run. The methoxy group on the central ring was important in inducing the effective conformation for ligand‐enzyme interaction. The drug‐likeness and pharmacokinetic properties were calculated via in silico predictions and showed an acceptable profile for these agents. According to our results, it was proposed that compound 6 l can serve as a drug candidate to develop more potent antityrosinase agents. [ABSTRACT FROM AUTHOR]

2‐Quinolinecarbaldehyde reacts with 1,3‐indandione to give 2‐[(3‐hydroxy‐1‐oxo‐1H‐inden‐2‐yl)(quinolin‐2‐yl)methylene]‐1H‐indene‐1,3(2H)‐dione, which is the first example of self‐oxidation of the Michael adducts of cycloalkanones with aldehydes. The structure of the product of oxidation is also proved by NMR and elemental analysis of its bromination product 2‐[(2‐bromo‐1,3‐dioxo‐2,3‐dihydro‐1H‐inden‐2‐yl)(1,3‐dioxo‐1,3‐dihydro‐2H‐inden‐2‐ylidene)‐methyl]quinolinium tribromide salt. The mechanism of this unusual reaction is studied experimentally and theoretically in comparison with that of a similar reaction with 2‐pyridinecarbaldehyde, which does not lead to self‐oxidation. The three‐step mechanism includes the formation of a pre‐reaction complex, which suffers proton transfer to the pyridinic nitrogen atom, and the hydride ion transfer to the protonated aldehyde. The transition states for the two reactions differ by the position on the reaction coordinate and the heights of the free energy barriers (~25 and ~4 kcal/mol), which allows to explain the observed different reactivity of the two similar hetaryl aldehydes. [ABSTRACT FROM AUTHOR]

A series of pyranocoumarins and benzocoumarins were synthesized by base‐mediated reaction of 4‐chloro‐3‐vinyl coumarins with cyclic 1,3‐dikeones in ethanol at reflux. Reactions using dimedone and 1,3‐cyclohexadione gave pyranocoumarins, whereas 1,3‐indandione resulted in the formation of unexpected benzocoumarin derivatives. These transformations were carried out under relatively green and mild conditions, provided access to novel coumarin‐based heterocycles in synthetically useful yields. [ABSTRACT FROM AUTHOR]