Ab initio studies of the protonation of CO,N2 and NO+: Calculation of the minimum energy reaction paths

Ab initio molecular orbital calculations employing a 4-31G basis set have been used to study the minimum energy paths for the formation of HCO⁺, COH⁺, and HCOH²⁺ from CO by protonation. The protonation of N₂ to give NNH⁺ and HNNH²⁺ and of NO⁺ to form HNO²⁺ and NOH²⁺ have also been investigated. All species formed have linear equilibrium geometries and the minimum energy path for approach of the proton is along the line-of-centers of the heavy atoms. Energy barriers to the formation of the various species are given, where appropriate, and changes in geometry, ordering of molecular orbitals and orbital occupancy are discussed.     

A study of complexation of chloral hydrate with heteropoly anions having various structures

¹H NMR was applied to study the interaction of chloral hydrate in deuterionitrobenzene solution with tetrabutylammonium salts of the heteropoly acids (HPA) belonging to five structural types: Keggin (H₃PW₁₂O₄₀, H₃PMo₁₂O₄₀, H₄SiW₁₂O₄₀), Dawson (-H₆P₂W₁₈O₆₂, -H₆P₂Mo₁₈O₆₂, -H₄S₂Mo₁₈O₆₂), H₆P₂W₂₁O₇₁(H₂O)₃, H₆As₂W₂₁O₆₉(H₂O), and H₂₁B₃W₃₉O₁₃₂. The surface of the HPA anions is nonuniform in acid-base properties. A general rule for all HPA was found, namely, that the HPA acidity increases with a decrease in the specific anion charge (per W or Mo atom).     

Complexation of 6-Deoxy-6-(aminoethyl)amino-β-cyclodextrin with Sodium Cholate and Sodium Deoxycholate

In order to study its guest binding and the inclusion phenomena, 6-deoxy-6-(aminoethyl)amino--cyclodextrin (CDN) was synthesised and its binding properties examined. The complexation phenomena of sodium cholate (NaC) and sodium deoxycholate (NaDC) with CDN has been monitored by the NMR method using ¹³C chemical shift data. The method of continuous variation Job's method has been used to determine the stoichiometry of these supramolecular complexes. The Job's plot confirms the 1 : 1 supramolecular complex for NaC: CDN and the 1 : 2 supramolecular complex for NaDC: CDN. The interaction of NaC and NaDC with CDN has been obtained through two-dimensional Rotational Nuclear Overhauser Effect Spectroscopy (ROESY) NMR. Equilibrium constants were also obtained from ¹³C chemical shift data (C-1, C-3 & C-4) at different pH values (7, 9, & 11).     

Synthesis of 2-Acetoxy- and 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyran

Summary 2-Acetoxy- and 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyranes were synthesized by decomposition of 1-hydroperoxy-1,2-dihydroacenaphthylene in acetic acid in the presence of perchloric acid.

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Synthese von 2-Acetoxy- und 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyran

Zusammenfassung 2-Acetoxy- und 2-Hydroxy-2,3-dihydronaphtho[1,8-bc]pyrane konnten durch Zersetzung von 1-Hydroperoxy-1,2-dihydroacenaphthylen in Essigsäure in Anwesenheit von Perchlorsäure synthetisiert werden.

     

ToF‐SIMS observation of PTFE surfaces modified by α‐particle irradiation

The surface structure of polytetrafluoroethylene (PTFE) upon α‐particle irradiation has been investigated at doses in the range of 1 × 10⁷ to 1 × 10¹¹ Rad and compared with the surface structure of the unirradiated polymer. Both neat and 25% fiberglass content PTFE were studied. The samples, maintained at nominal room temperature, were irradiated in vacuum by 5.5 MeV ⁴He²⁺ ions generated in a tandem accelerator beam line. Static time‐of‐flight SIMS (ToF‐SIMS) was employed to probe chemical changes at the surface as a function of the irradiation level. In general, the data are indicative of increased cross‐linking at α‐doses less than 1 × 10⁹ Rad, followed by increased fragmentation and unsaturation at α‐doses greater than 1 × 10⁹ Rad. Throughout the irradiation regime, scission is a constant factor promoting cross‐linking, branching, and unsaturation. However, at α‐doses greater than 1 × 10¹⁰ Rad, extreme structural degradation of the polymer becomes evident and is accompanied by conversion to oxygen‐functionalized and aliphatic compounds. Thus, for PTFE in an α‐particle field, an upper exposure limit of ～10¹⁰ Rad is essential for nominal retention of molecular structure. Finally, a quantitative relationship between α‐dose and characteristic fragment ion intensity is developed. Copyright © 2005 John Wiley & Sons, Ltd.     

A facile method for the synthesis of 3,1-benzooxazines from N-acyl-2-(alk-2-enyl)anilines

Electrophilic addition of HCl or Br₂ to N-acyl-2-(alk-2-enyl)anilines is accompanied by intramolecular cyclization of these amides to give 3,1-benzooxazine hydrochlorides or hydrobromides in high yields.     

Synthesis of 2-(α-Hydroxyalkyl)-2-Oxazoline under Microwave Irradiation in Bluk

Four 2-(α-hydroxyalkyl)-2-oxazolines and a 2-(α-hydroxy-α,α-diphenyl)-2-benzooxazole were synthesized from β-amimoalcohols and α-hydroxy carboxylic acids under microwave irradiation in the absence of a solvent.     

用环加成反应合成含氟杂环化合物的研究

综述了近年来利用一些新型的含氟砌块，通过它们的环加成反应来高效地合成 含氟杂环化合物的研究，其中包括以下两个部分：(1)用1，3—偶极环加成反应合 成五元含氟杂环化合物；(2)用杂原于Diels-Alder反应合成六元含氟杂环化合物．     

Critical Analysis of Hypothesis Tests in Federal Information Processing Standard (140-2)

This work presents an analysis of the existing dependencies between the tests of the FIPS 140-2 battery. Two main analytical approaches are utilized, the first being a study of correlations through the Pearson’s correlation coefficient that detects linear dependencies, and the second one being a novel application of the mutual information measure that allows detecting possible non-linear relationships. In order to carry out this study, the FIPS 140-2 battery is reimplemented to allow the user to obtain p-values and statistics that are essential for more rigorous end-user analysis of random number generators (RNG).     

A Novel Strategy for Regulating mRNA’s Degradation via Interfering the AUF1’s Binding to mRNA

The study on the mechanism and kinetics of mRNA degradation provides a new vision for chemical intervention on protein expression. The AU enrichment element (ARE) in mRNA 3′-UTR can be recognized and bound by the ARE binding protein (AU-rich Element factor (AUF1) to recruit RNase for degradation. In the present study, we proposed a novel strategy for expression regulation that interferes with the AUF1-RNA binding. A small-molecule compound, JNJ-7706621, was found to bind AUF1 protein and inhibit mRNA degradation by screening the commercial compound library. We discovered that JNJ-7706621 could inhibit the expression of AUF1 targeted gene IL8, an essential pro-inflammatory factor, by interfering with the mRNA homeostatic state. These studies provide innovative drug design strategies to regulate mRNA homeostasis.