In this paper, we introduce a novel and convenient method for the transformation of heterocyclic amides into heteocyclic thioamides. A two-step approach was applied for this transformation: Firstly, we applied a chlorination of the heterocyclic amides to afford the corresponding chloroheterocycles. Secondly, the chloroherocycles and N-cyclohexyl dithiocarbamate cyclohexylammonium salt were heat...

We report two-dimensional (2D) (17)O multiple-quantum magic-angle spinning (MQMAS) NMR spectra for four (17)O-labeled organic compounds: [(17)O(2)]-D-alanine (1), potassium hydrogen [(17)O(4)]dibenzoate (2), [(17)O(4)]-D,L-glutamic acid.HCl (3) and [2,4-(17)O(2)]uracil (4). The high spectral resolution observed in the 2D (17)O MQMAS NMR spectra allows extraction of precise (17)O NMR parameters ...

An overview is presented of the methodology and computations of nuclear shielding and spin–spin coupling constants of transition metal complexes. The presented material also includes an outline of relativistic approaches and their applications to heavy transition metals.

Periodic density functional theory (DFT) calculations have recently emerged as a popular tool for assigning solid-state nuclear magnetic resonance (NMR) spectra. However, in order for the calculations to yield accurate results, accurate structural models are also required. In many cases the structural model (often derived from crystallographic diffraction) must be optimised (i.e., to an energy ...

We have selectively deuterated the sidechain of the synthetic polypeptide poly (-y-benzyl-L-glutamate), PBLG. In magnetically oriented nematic solutions of PBLG, the helical polymer rods are aligned parallel to the field. The Brownian motion of the flexible PBLG sidechain is anisotropic, resulting in quadrupole splittings of the 2H NMR resonances. The order parameters of C-D bond directions in ...

Glycosaminoglycans (GAGs) comprise a special class of complex carbohydrates endowed with numerous biological functions. Most of these functions are regulated by conformational arrangements or dynamical properties of GAGs in solution. Nuclear magnetic resonance (NMR) is a powerful technique used for dynamic analyses. Spin relaxation, scalar couplings, chemical shifts and nuclear Overhauser effec...

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...

Even though there were actually a number of established scientists in attendance, the meeting seemed to be geared toward graduate students and postdocs. Many of the presentations focused on giving advice about and descriptions of the process of structural determination. There was little actual discussion of either algorithms or biology, but many of the opinions were quite thought provoking and ...