triphenyl phosphine(pph3), an efficient and reusable catalyst, catalysed the synthesis of 2-amino-3-cyano-6-methyl-4-aryl-4h-pyran-5-ethylcarboxylate derivatives by one-pot condensation of aromatic aldehydes, malononitrile and ethyl acetoacetate in etoh-h2o (1:1) at reflux conditions. the results show that aromatic aldehydes containing electron-donating groups or electron-withdrawing groups cou...

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

1,3-Dipolar cycloaddition of dihydropyran derived nitrones synthesized from 2,3 dihydro 4H-pyran and various hydroxylamines, with electron deficient alkynes are found to have significant rate acceleration and improved yields of isoxazolines in 1-Butyl-3-methylimidazolium based ionic liquids while with enals exclusively endo isoxazolidines are obtained with high selectivity. Synthetic potentiali...

An efficient and green method has been developed for the synthesis of new substituted Hantzsch thiazole derivatives in 79%-90% yield, via the one-pot multi-component procedure, by the reaction of 3-(bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, thiourea and substituted benzaldehydes in the presence of silica supported tungstosilisic acid, as a reusable catalyst, under conventional heating or ...

H etero-Diels-Alder Reaction, a,/?-Unsaturated Ketones, Styrenes Cycloadditions of 3-aryl-2-benzoyl-2-propenenitriles la,b to styrene (2a) and its methylor methoxy-substituted derivatives 2b-d proceed regioand diastereoselectively yielding cis and trans diastereoisomers of 2,4,6-triaryl-3,4-dihydro-2//-pyran-5-carbonitriles 3 and 4 in 59-72% yield. Cycloadducts cis-3 were the major products. Re...

N-Heterocyclic carbene-catalyzed reaction of 2-aroylvinylcinnamaldehydes with 2-aroylvinylchalcones proceeded via a triple Michael addition and intramolecular lactonization cascade to produce novel 9-(2-aroyl-3-aroylmethyl-1-indanyl)-3-arylindeno[2,1-c]pyran-1-ones in good yields with high diastereoselectivity. This reaction constructed six contiguous stereogenic centers in a single reactive ev...

Commercial dehydroacetic acid was converted into 4-hydroxy-6-methylpyridin-2(1H)-one (3), which was then condensed with several aliphatic aldehydes to produce seven new title compounds in variable yields (35-92%). Reaction of 3 with alpha,beta-unsaturated aldehydes resulted in the formation of condensed pyran derivatives 4g' and 4h'. A mechanism is proposed to explain the formation of such comp...

In the present research, silica bonded n-propyl-1,3,5-triazine-2,4,6-triamine (SPTT) was synthesized by direct incorporation of chloropropyl groups through co-condensation of tetraethyl orthosilicate (TEOS) and 3-chloropropyl trimethoxysilane (CPTMS) and subsequent grafting the melamine onto the propyl groups via simple nucleophilic substitution reaction. The catalyst has been characterized by ...

Regioselective sulfamoylation of primary hydroxyl groups enabled a 5-step synthesis (overall yield 17%) of the first reported small molecule inhibitor of sulfatase-1 and 2, ((2S,3R,4R,5S,6R)-4,5-dihydroxy-2-methoxy-6-((sulfamoyloxy)methyl)tetrahydro-2H-pyran-3-yl)sulfamic acid, which obviated the use of hydroxyl protecting groups and is a marked improvement on the reported 9-step synthesis (ove...

We report the synthesis and the optoelectronic characterization of three new 4H-pyran-4-ylidene and thiazole derivatives (pyt) as metal-free organic dyes for solid-state dye-sensitized solar cells (DSSCs). We investigate the performance and the long-term stability of devices employing pyt dyes functionalized with carboxylic and phosphonic acids as TiO2 anchoring groups. In contrast to reports o...