A New and Convenient Synthesis of 3(2H)-Pyridazinones by Reacting Carbanion of Ethyl Trimethylsilylacetate with Phenylhydrazones

A one-pot synthesis of 5,6-disubstituted-2-phenyl-3(2H)-pyridazinones 4 is achieved on treatment of carbanion of ethyl trimethlsiylacetate with phenylhydrazones of 1,2-dicarbonyl compounds 1.     

Structural and Electronic Properties of Neutral and Ionic GanOn Clusters with n = 4—7

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Synthesis of new bridgehead heterocycles: Pyrimido[3′,2′:3,4]‐1,2,4‐triazino[5,6‐b]indoles

A new bridgehead nitrogen hetero‐ cycle viz. 11‐carboethoxy‐9‐oxo‐pyrimido[3′2′:3,4]‐1,2,4‐triazino[5,6‐b]indole 3 has been synthesized from 3‐azido‐5H‐1,2,4‐triazino[5,6‐b]indole 2 by its reaction with diethyl fumerate. The intermediate 2 was obtained by treating 3‐hydrazino‐5H‐1,2,4‐triazino[5,6‐b]indole with NaNO₂ in presence of polyphosphoric acid. A plausible mechanism for the formation of 3 has been formulated and discussed. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:272–276, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20199     

Stereoselective Synthesis for Potential Isomers of Ticagrelor Key Starting Material

Tartrate salt of carbocyclic amine 2 is one of the key starting materials for the synthesis of Ticagrelor 1 . During the synthesis of 1 , the isomers of 2 also need to be considered as potential impurities and characterized before establishing the specification of product. In the present work, detailed study has been carried out to synthesize the related substances of 2 , and their structure characterization has been discussed.     

Size effect on organic optoelectronics devices: Example of photovoltaic cell efficiency

Electromagnetic study of organic photovoltaic cells design shows that electrical parameters depend drastically on the active area geometry: we theoretically show that electrical parameters are altered when the cell length becomes greater than one centimeter. Experimental verification is provided with simple molecular heterojunction cells with areas from 0.03 to 0.78 cm².     

Polyesters with Aromatic Groups in the Backbone from Reactions of 3- and 4-Bromomethylbenzoic Acids with Triethylamine

Abstract

Aromatic polyesters were obtained in relatively good yields (～ 70%) from reactions of 3- and 4-bromomethylbenzoic acids with tri-ethylamine in chlorobenzene. A copolymer was prepared in 58% yield by reaction of a 1:1 mixture of the two acids under similar conditions. The polyesters were characterized by IR, ¹H- and ¹³3C-NMR spectra, x-ray powder diffraction, DSC behavior, solution viscosity, and hydrolysis to the corresponding hydroxymethylbenzoic acids. Molecular weights were determined by ¹H-NMR endgroup analysis. Possible mechanisms for the reactions are discussed.     

Green luminescent ZnO:Cu<Superscript>2+</Superscript> nanoparticles for their applications in white-light generation from UV LEDs

Copper doped ZnO nanoparticles were synthesized by a chemical technique based on a hydrothermal method. The crystallite sizes, estimated by XRD and TEM/SEM for different doping percentage of Cu²⁺ (1–10%), were found to be in the range of ~10–15 nm. TEM/SEM images showed formation of uniform nanorods, the aspect ratio of which varied with doping percentage. Photoluminescence (PL) measurement showed strong green visible emission and PL intensity was found enhanced with increase in doping percentage. The increase in the PL intensity was mainly due to Cu incorporation in ZnO lattice. Currently, light-emitting diodes (LEDs) giving ultraviolet emission have been combined with broad-band visible green phosphors to make white-light LEDs. Thus, green luminescent ZnO:Cu²⁺ nanoparticles are seen as necessary and condemnatory constituent for white-light generation from UV LEDs, underlying the importance of the current work.     

Location coverage models with demand originating from nodes and paths: Application to cellular network design

Location covering problems, though well studied in the literature, typically consider only nodal (i.e. point) demand coverage. In contrast, we assume that demand occurs from both nodes and paths. We develop two separate models – one that handles the situation explicitly and one which handles it implicitly. The explicit model is formulated as a Quadratic Maximal Covering Location Problem – a greedy heuristic supported by simulated annealing (SA) that locates facilities in a paired fashion at each stage is developed for its solution. The implicit model focuses on systems with network structure – a heuristic algorithm based on geometrical concepts is developed. A set of computational experiments analyzes the performance of the algorithms, for both models. We show, through a case study for locating cellular base stations in Erie County, New York State, USA, how the model can be used for capturing demand from both stationary cell phone users as well as cell phone users who are in moving vehicles.     

l-Proline catalyzed multicomponent reaction of 3,4-dihydro-(2H)-pyran, urea/thiourea, and aldehydes: diastereoselective synthesis of hexahydropyrano pyrimidinones (thiones)

An organocatalytic multicomponent reaction involving 3,4-dihydro-(2H)-pyran, aromatic aldehydes, and urea/thiourea as substrates and l-proline/TFA as catalyst afforded hexahydropyrano pyrimidinones (thiones) in good yields. The method is simple, economical, and ecofriendly to generate hexahydropyrano pyrimidinones as precursors for many biologically active molecules and fused oxazines (PA-824), the lead molecules for tuberculosis chemotherapy.