A tunable circularly polarized distributed feedback (DFB) laser based on reflection grating configuration was realized in a solution of 4- (dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) doped methanol. Chiral photonic DFB structures with tunable photonic bandgap were generated by controlling the state of polarization of the two interfering pump beams. The dual-peak lasing ...

Lasing action in an electrically pumped organic laser device is demonstrated with a high quality factor (Q) microcavity structure formed by two high-reflective and low-loss electrical contacts. A 4-(dicyanomethylene)-2-i-propyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran-doped tris(8-hydroxy-quinoline)aluminum (Alq(3)) film serves as the active layer. A single longitudinal lasing cavity mo...

We present a detailed study of the gain length in an active medium obtained by doping of DNA strands with 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran dye molecules. The superior thermal stability of the composite and its low quenching permit one to obtain an optical gain coefficient larger than 300 cm(-1). We also demonstrate that such an active material is feasible for the...

A rapid and environmentally friendly method is developed for the synthesis of a series of new substituted 2-amino-4H-pyran-3-carbonitriles through a one-pot condensation of malononitrile and α, α'-bis(arylidene) cycloalkanones in ethanol by using K(2)CO(3) as a catalyst. Short experimental reaction times, excellent yields, no need to use cumbersome apparatus for purification of the products, an...

An enantioselective (52-98% ee) Michael addition between cyclic β-diones and α,β-unsaturated enones was established in the presence of quinine-based primary amine or squaramide. A variety of cinnamones were smoothly converted into the desired 3,4-dihydropyrans in moderate to high yields (63-99%). Chalcones were also suitable acceptors and gave rise to the expected adducts in satisfactory yields...

Mariannaeapyrone ((E)-2-(1,3,5,7-tetramethyl-5-nonenyl)-3,5-dimethyl-6-hydroxy-4H-pyran-4-one) is a new fungal metabolite isolated from fermentations of the common mycophilic deuteromycete Mariannaea elegans. The chemical structure of the 4-pyrone was determined by spectroscopic techniques. Mariannaeapyrone is a selective inhibitor of the thromboxane A2 induced aggregation of human platelets, w...

In the xanthene ring system of the title compound, C(23)H(25)BrO(4), the 4H-pyran ring is almost planar [maximum deviation = 0.040 (3) Å] and the cyclo-hexene ring adopts a sofa conformation. The cyclo-hexene ring attached to the xanthene system is puckered [Q(T) = 0.427 (3) Å, θ = 55.0 (4) ° and ϕ = 164.4 (6) °]. In the crystal, mol-ecules are linked to each other by O-H⋯O and C-H⋯O hydrogen b...