In this paper, we report the application of the QM/QM hybrid simulation technique to the photoisomerisation reactions of anils (i.e., Schiff bases of salicylaldehyde with aniline derivatives) in the solid state, on the example of the photochromic polymorph of N-salicylidene-2-chloroaniline. By propagating molecular dynamics on a potential energy surface constructed using a combination of time-d...

SYNLETT 2010, No. 11, pp 1712–1716xx.xx.2010 Advanced online publication: 14.06.2010 DOI: 10.1055/s-0030-1258094; Art ID: Y00510ST © Georg Thieme Verlag Stuttgart · New York Abstract: The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing t...

The structure of the genetic code implies strict Watson-Crick base pairing in the first two codon positions, while the third position is known to be degenerate, thus allowing wobble base pairing. Recent crystal structures of near-cognate tRNAs accommodated into the ribosomal A-site, however, show canonical geometry even with first and second position mismatches. This immediately raises the ques...

Novel 1,3-Dimethyl-5-propionylpyrimidine-2,4,6(1H,3H,5H)-trione was synthesized and recrystallized from ethanol. The compound was characterized by 1H NMR, 13C NMR in CDCl3, DMSO-d6 and acetone-d6, elemental analysis and X-ray diffraction. The NMR data observed that the title compound exists in the enol tautomer rather than keto, and it stabilized by strong H-bond as observed form the NMR data a...

The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a non-polar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a keta...

The idea of the enol form of nucleotides being responsible for the formation of some noncanonical pairs was put forward by Watson and Crick in their first paper on DNA structure [1]. In the context of this hypothesis, the GU pair may contain either the enol form of uracil and the keto form of guanine or the enol form of guanine and the keto form of uracil. Later, in 1966, Francis Crick proposed...

Dynamic chirality of iminoresorcin[4]arenes that originates from regioselective and diastereoselective keto-enol tautomerisation was switched by non-covalent interactions with achiral molecules, as demonstrated by experimental electronic circular dichroism (ECD) spectra supported by TD DFT calculations.

Die spektrale Abstimmung der Elektrochemilumineszenz (ECL) von Luciferin – grün nach rot wird durch Elektrolyt-Engineering erreicht, was zeigt, dass dafür keine Keto/Enol-Isomerisierung des Emitters erforderlich ist. visuelle Darstellung ECL ermöglicht eine unkomplizierte optische Messung Superoxid-Diffusivität, wie Michelle L. Coote, Marco Garavelli, Simone Ciampi et al. in ihrem Forschungsart...

The role of general acid-base catalysis in the enzymatic mechanism of NADP+-dependent malic enzyme was examined by detailed steady-state kinetic studies through site-directed mutagenesis of the Tyr(91) and Lys(162) residues in the putative catalytic site of the enzyme. Y91F and K162A mutants showed approx. 200- and 27000-fold decreases in k(cat) values respectively, which could be partially rec...