in this research, the microstructural of low molecular weight 1,2-polybutadiene (1,2-pbd) was conducted by 1h and 13c nuclear magnetic resonance spectroscopy (nmr) to determine the isomeric contents of 1,4-cis, 1,4-trans and 1,2-vinyl in 1,2-pbd polymer structures. number average molecular weight for low molecular weight 1,2-pbd was measured by nmr techniques and the results were compared with ...

This article addresses the problem of the computation of instantaneous firing speed in Invariant Behavior state (IB-state) of Constant speed Continuous Petri Net (CCPN) with presence of actual conflicts. The adopted approach is based on polyhedral computations applied to specify an area of possible instantaneous firing speed. If the actual conflicts are resolved by global priorities, the instan...

We have evaluated the NMR shielding tensors for A:T,G:C,A:U in Watson-crick, and U-quartet. We have computed NMR shielding tensors at B31YP level by using 6-31G(d) basis set. We have compute anisotropy and asymmetry in A:T,G:C,A:U and U-quartet. The NMR shielding tensors were calculated using the GIAO method. The natural bonding orbital analysis (NBO) were performed. NBO calculation have been ...

Phytochemical examination of corncob extracts led to the isolation of a new lignan identified as 7,7'-dihydroxy-3'-O-demethyl-4-methoxymatairesinol, together with seven known compounds, identified as β-sitosterol, β-sitosteryl-β-D-glucoside, 6β-hydroxy-campest-4-en-3-one, 5α,8α-epidioxyergosta-6,22-dien-3β-ol, tricin, kaempferol and p-coumaric acid. The isolated compounds were identified by one...

α-acyloxycarboxamides are synthesized from three component Passerini reaction between indane-1,2,3-trione, isocyanides, and thiophenecarboxylic acids in quantitative yields. The structures of the final products were confirmed by IR, 1H and 13C NMR spectroscopy, mass spectrometry, and elemental analysis. The B3LYP/HF calculations for computation of 1H an...

Nuclear magnetic resonance (NMR) is a physical phenomenon based upon the quantum mechanical magnetic properties of an atoms nucleus. Thereby NMR spectroscopy is a technique to obtain physical, chemical and structural information about molecules. Recent research is focused on the analysis of small molecules, e.g. metabolites by NMR or in a combination of NMR and electro spray ionization mass spe...

2-Amino-substituted ketones react with α-methylene ketones under solvent-free conditions at 90 °C in thepresence of a catalytic amount of zirconium dodecylphosphonate to create the corresponding quinolinesin excellent yields. This procedure recommends numerous advantages such as easy work-up, use of mild,reusable and safe catalyst, short reaction timeand high yields. The new compounds have been...