Abstract To find novel classes of potential fuel additives multivalent activity, particularly antioxidants, a series recently synthesized ethyl-6-amino-5-cyan-methyl-4-aryl-4H-pyran-3-carboxylates have been investigated using model oxidative reactions. The compounds studied appear to be prospective inhibitors hydrocarbons oxidation. Some them are antioxidants combined action, breaking the chain...

Wells–Dawson tungsten heteropolyacid (H6P2W18O62) has been applied as an effective heterogeneous catalyst for one-pot synthesis of spiro[4H-pyran-3,3’-oxindoles] via reaction of various isatins, malonitrile and 1,3-dicarbonyl compound in water. The corresponding products were obtained in high yields. The catalysts were easily recycled and reused without loss of their catalytic activity. 

Egg shell has been utilized as a natural, green, reusable and eco-friendly reagent for the synthesis of spiro[4H-pyran-oxindole] derivatives by one-pot multicomponent reaction of isatins, 1,3-diketones, and malononitrile/ ethyl cyanoacetate. Good functional group tolerance and broad scope of usable substrates are other prominent features of the present methodology.

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 ...