Regioselective Reaction of N1-Benzyl-N2-(4-nitrophenyl)ethanediamide and Acetylenic Esters

The regioselective reaction of N¹-benzyl-N²-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields.     

Using a Natural Surfactant for Synthesize of NiO and CuO Nanostructures via Simple and Fast Microwave Approach

NiO and CuO nanostructures were synthesized successfully via simple and fast microwave approach. Olive oil was chose as surfactant for stabilizing nanostructures. Different parameters such as microwave time and power and olive oil concentration were investigated on product size and morphology. The products were characterized with X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and energy dispersive spectrometry analysis.     

Detectability conditions for output-only subspace identification

ABSTRACT

The scope of output-only/blind identification is restricted to stochastic/statistical processes, but for the first time in this study, the detectability conditions for general output-only subspace identification are investigated. This aids the range of input sources to be extended in a much realistic manner, beyond the only stochastic inputs. For this purpose, the subspace framework is assigned to make a connection between the output signal contents and the LTI system order. A few substantial hypotheses and algebraic statements are propounded affirming the sufficiency of the genuine output sequences for the identification purpose. This can be perceived as the cornerstone of state-space model reconstruction. In order to consolidate the notions according to reality, several examples are studied and examined for different input classes with stochastic disturbance.     

Conversion of Thiols to Disulfides Using a Hexamethylenetetramine-Bromine Complex

Hexamethylenetetramine-bromine complex, a yellow-orange, very stable homogeneous solid, affects a mild and fairly general conversion of thiols to disulfides.     

Ab Initio Study of Conformational Properties of Heteroatom-Containing 1,2-Bisketene Analogues

Abstract

Minimum-energy and transition-state geometries of 4-oxobuta-1,3-diene-1-thione, buta-1,3-diene-1,4-dithione, 4-selenoxobuta-1,3-diene-1-thione, 4-selenoxobuta-1,3-diene-1-one, and buta-1,3-diene-1,4-diselenone were calculated using HF, B3LYP, and MP2 levels of theory and 6–31 + G* basis set by rotation around the related ?C?C? single bonds. In all of the above-mentioned molecules, the s-trans conformation was obtained as the most stable conformer with the 180° dihedral angle. In buta-1,3-diene-1,4-dithione, 4-selenoxobuta-1,3-diene-1-thione, and buta-1,3-diene-1,4-diselenone, the s-cis form of these compounds corresponded to the other energy-minimum geometry. Their skew geometries, with torsional angles approximately 100°, were a transition state for conformational interconversion between the two global minima forms. In 4-oxobuta-1,3-diene-1-thione and 4-selenoxobuta-1,3-diene-1-one, geometries with the C?C?C?C dihedral angles about 51 and 43° (respectively) were attributed to the second energy-minimum geometry. Transition-state structures from both molecules were found in the torsional angles at about 0 and 100°.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT