an efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [bo3h3 or b(oh)3] as an inexpensive and reusable catalyst is described. the salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...

poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14h-dibenzo [a-o] xanthenes under solvent-free conditions. this catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.

This paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (DOXOs) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. This novel synthetic method has the advantages of high yields, short reaction times, low cost and av...

A simple and environmentally benign procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [Et3NH][HSO4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...

This paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (DOXOs) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. This novel synthetic method has the advantages of high yields, short reaction times, low cost and av...

The indium(III)-catalyzed cascade cycloisomerization reaction of 1,5-enynes with pendant aryl nucleophiles is reported. proceeds in under mild conditions, using InI3 (5 mol %) as a catalyst range furnished groups (phenyl and phenol) at alkene (E Z isomers) terminal internal alkynes. Using 1-bromo-1,5-enynes, one-pot sequential indium-catalyzed palladium-catalyzed cross-coupling triorganoindium ...

A new class of rhodamines for the application as indicator dyes in fluorescent pH sensors is presented. Their pH-sensitivity derives from photoinduced electron transfer between non-protonated amino groups and the excited chromophore which results in effective fluorescence quenching at increasing pH. The new indicator class carries a pentafluorophenyl group at the 9-position of the xanthene core...

The intensity of two-photon-excited fluorescence measured relative to the intensity of hyper-Rayleigh scattering in the same apparatus was used to determine the two-photon-excited fluorescence cross sections of the xanthene dyes Rhodamine B, Rhodamine 6G, and Fluorescein. The measured cross sections at l0 5 1064 nm are s2PF (2) 5 1.5 6 0.3 3 10250 cm4 s, 2.0 6 0.4 3 10250 cm4 s, and 1.4 6 0.3 3...