Abstract Tautomerism is one of the most important phenomena to consider when designing biologically active molecules. In this work, we use NMR spectroscopy, IR, and X-ray analysis as well quantum-chemical calculations in gas phase a solvent study tautomerism 1- (2-, 3- 4-pyridinecarbonyl)-4-substituted thiosemicarbazide derivatives. The tautomer containing both carbonyl thione groups turned out...

In response to the changing market pressures being applied to the pharmaceutical industry, a greater emphasis is being made to advance new drugs to market with minimal investment in early development stages. The use of quantitative NMR (q-NMR) has been shown to be a single point replacement for routine early development testing which previously combined elements of identity testing, chromatogra...

We have evaluated the NMR shielding tensors for active site of oxidized ayurin Azurin is classified to atype I copper protein with ET functionality. We have computed NMR shielding tensor at .133LYP and IDlevels by usum 6-3IG basis set in the gas phase and in different solvents such as water, HMSO,Nitromethane, methanol, ethanol, acetone ,dicholoroethane. These solvents represent a wide range of...

The absence of adequate force field (FF) parameters to describe certain metallic complexes makes new and deeper analyses impossible. In this context, after a group researchers developed validated an AMBER FF for platinum complex (PC) conjugated with AHBT, possibilities emerged. Thus, in work, we propose improved path obtain NMR spectroscopic parameters, starting from specific PC, allowing more ...

Molecular orbital calculations have been carried out on 2-fluorotetrahydropyran and 2-chlorotetrahydropyran as models for examining the anomeric effect in glycosyl halides. The calculated population of chair conformers depends on the solvent and for the axial form of fluoro derivative decreases from 90.6 % in dioxan to 37.0 % in water. For chloro derivative the dependence is less pronounced; th...

All-atom molecular simulations and two-dimensional nuclear overhauser effect spectrum have been used to study the conformations of carnosine in aqueous solution. Intramolecular distances, root-mean-square deviation, radius of gyration, and solvent-accessible surface are used to characterize the properties of the carnosine. Carnosine can shift between extended and folded states, but exists mostl...

(‒)-Encecanescin (1) has been isolated from the leaves of Eupatorium aschembornianum. Two conformers are present in the crystal structure as a result of molecular disorder. The structure of 1 was established by 1H- and 13C-NMR spectroscopy in CDCl3 solution using 2D NMR techniques (gHSQC, gHMBC and NOESY). A Monte Carlo random search using molecular mechanics followed by the geometry optimizati...

Three fluorescent asymmetric bis-urea receptors (L1-L3) have been synthesised. The binding properties of L1-L3 towards different anions (fluoride, acetate, hydrogencarbonate, dihydrogen phosphate, and hydrogen pyrophosphate HPpi(3-)) have been studied by means of (1)H-NMR, UV-Vis and fluorescence spectroscopy, single crystal X-ray diffraction, and theoretical calculations. In particular, a rema...