One pot synthesis of polymer protected gold nanoparticles and nanoprisms in glycerol

Uniform and stable polymer protected spherical gold nanoparticles were synthesized using glycerol as reducing agent. Further it was observed that the morphology of the particles varied from spherical to triangular prismatic gold nanoparticles when the reaction was changed from normal mode of reflux condition to microwave mode (MW) of heating. Further a brief mechanism relating the formation of prisms with the orientation of polymer and nucleation period has been discussed. Formation of triangular prismatic and spherical gold nanoparticles were characterised using UV–vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis.     

The preparation of some 1-(2-furyl)-2-arylethylenes

Some 1-(2-furyl)-2-arylethylenes, where the furan nucleus is substituted in position 5 with a methyl or p-chlorophenyl group and where the aryl group is phenyl, p-nitrophenyl, α-naphthyl or β-naphthyl, have been prepared by the Perkin reaction and subsequent decarboxylation of the acid. The compounds 1-12 were prepared lor of photochemistry and photoelectron spectroscopy studies. Their geometrical configurations has been established by ¹H nmr and ir spectra.     

Chemical and photochemical synthesis of substituted dihydro-thieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones and tetrahydro-dithieno[2,3-b:2',3'-d]thieno[2'',3''c:2'',3''c']diquinolin-6,14-dione

Some new substituted dihydrothieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones 9- 12 and tetrahydrodithieno[2,3-b: 2',3'-d]thieno[2',3'-c:2',3'-c']diquinolin-6,14-dione (17) were prepared from the corresponding new anilides 5-8 and from the corresponding dianilide 15, respectively, by a multistep combination of chemical and photochemical reactions. All the prepared compounds are of particular interest because they might serve as DNA intercalators in anticancer therapy.     

Ab initio studies of negative ion-molecule(s) clusters present in the atmosphere. II. OH−(H2O)n for n = 0, 2, 3, 4

Ab initio calculations are performed with 6–31G basis set to study the geometry and binding of the H₃O, H₅O, H₇O, and H₉O complexes. The H₃O complex is also investigated with the 6–31 G* basis set and MP 2 (Moller–Plesset perturbation theory of second order).     

Spektroskopische Untersuchung einiger α,β-ungesättigter cyclischer Ketone

The results of the spectroscopic investigation of the steroidal enones 1–6 can be summarized as follows:

• 1. Direct absorption and phosphorescence excitation techniques have been used to locate the ³(n,π*) states, and in each case it has been found to be the second triplet state.
• 2. The lowest excited state in each case is assigned as ³(π,π*) state.
• 3. The diffuseness in the phosphorescence emission from the ³(π,π*) states is attributed to a large change in the molecular geometry upon excitation (probably to a non-planar configuration).
• 4. The diffuseness in the S→ T_n,π* absorption is correspondingly attributed to interaction between the ³(n,π*) and ³(π,π*) states. A summary of the energy levels for these compounds is given in Fig. 4.

     

Novel 3-phenylprop-2-ynylamines as inhibitors of mammalian squalene epoxidase

The synthesis of a novel series of 3-phenylprop-2-ynylamines as selective mammalian squalene epoxidase inhibitors is described. Structure activity relationship studies led to the discovery of compound 19, 1-[3-(3,5-dichlorophenyl)-prop-2-ynyl]-3- methylpiperidine hydrochloride with an IC50 of 2.8 +/- 0.6 microM against rat liver squalene epoxidase. Against 23 strains of fungal squalene epoxidase compound 19 was found to be inactive.     

An in situ silver cationization method for hydrocarbon mass spectrometry

We have developed a novel cationization method for the analysis of long-chain hydrocarbons via UV laser desorption mass spectrometry. In this technique we electrospray a thin coating of AgNO3 over a sample and perform UV laser desorption to produce Ag+ cationization of sample molecules. Use of this technique in our microscope/TOF-MS allows us to determine the spatial distribution of the species we detect in the sample. We demonstrate 8-mu spatial resolution, and submicron resolution is possible in principle. In mixed samples containing aromatic and aliphatic compounds, the aromatic compounds ionize directly and do not form adducts, and thus give single peaks as opposed to doublets from silver cations. This enables distinction between aromatic and aliphatic compounds that are in the same sample.     

Microwave-assisted one-pot synthesis of 2,3-disubstituted 3H-quinazolin-4-ones

A practical synthesis of 2,3-disubstituted 3H-quinazolin-4-ones 1 with broad chemistry scope is described. The key step is the microwave promoted one-pot, two-step reaction sequence combining anthranilic acids, carboxylic acids, and amines providing efficient access to this important class of heterocycles.     

Directed ring-opening of 1,5-dioxaspiro[3.2]hexanes: selective formation of 2,2-disubstituted oxetanes

1,5-Dioxaspiro[3.2]hexanes undergo ring-opening reactions with many heteroatom nucleophiles to provide alpha-substituted-beta'-hydroxy ketones. However, certain Lewis acidic nucleophiles provide 2,2-disubstituted oxetanes. Herein, the results of reactions of 3-phenyl-1,5-dioxaspiro[3.2]hexane with a variety of nitrogen-containing heteroaromatic bases are reported. There appears to be a correlation between the pK(a) of the nucleophile and the reaction outcome with more acidic nucleophiles providing 2,2-disubstituted oxetanes. Moreover, the mode of ring opening can be directed toward the substituted oxetane by the addition of a Lewis acid. These results are rationalized by calculation of stationary points on the potential energy surfaces for the various possible reaction pathways using ab initio molecular orbital methods.     

An oscillation criterion for functional differential equations with deviating arguments

An oscillation criterion is given for the differential equation