Mechanisms of nitric oxide generation in living systems.

In modern chemical and biochemical studies, special attention is paid to molecular systems capable of generating nitric oxide (NO), which is one of the most important signalling molecules in the body and can trigger a whole cascade of reactions. Despite the importance of this molecule, the mechanisms of its formation in living organisms remain a subject of debate. This review combines the most important methods of releasing NO from endogenous and exogenous sources.

Lithium-Promoted Cycloaddition of Indole-2,3-dienolates and Carbon Disulfide as a One-Pot Route to Thiopyrano[4,3-]indole-3(5)-thiones.

A new approach for the annulation of a thiopyrane ring to an indole core under mild conditions was developed. Treating 2-methyl-3-acylindoles with lithium diisopropyl amide leads to the elimination of a proton from the 2-methyl group. The lithium indole-2,3-dienolates obtained were found to react with CS to give the corresponding thiopyrano[4,3-]indole-3(5)-thiones.

From 3-Acyl-2-methylindoles to γ-Carbolines: Li-Promoted Cycloaddition Reaction and Its Quantum Chemical Study.

A one-pot cycloaddition strategy for obtaining γ-carbolines under mild conditions was developed. The reaction represents a new approach to the annulation of a pyridine ring to an indole core. Treating 2-methyl-3-benzoylindoles with lithium diisopropyl amide leads to the elimination of a proton from the 2-methyl group.

Comprehensive study of nitrofuroxanoquinolines. New perspective donors of NO molecules.

The goal of present work is the study of NO releasing mechanisms in nitrofuroxanoquinoline (NFQ) derivatives. Mechanisms of their structural non-rigidity and pathways of NO donation - spontaneous or under the action of sulfanyl radicals or photoirradiation - were considered in details, both experimentally and quantum chemically. Furoxan-containing systems of the discussed type are not capable of spontaneous or photoinduced decomposition under mild conditions, and sulfanyl (radical) induced processes are the most preferable.

Non-canonical DNA structures: Comparative quantum mechanical study.

A study of relative thermodynamic stability of non-canonical DNA structures (triplexes, G-quadruplexes, i-motifs) for the first time was conducted on the basis of quantum chemical DFT/B3LYP/6-31++G (d) calculations. Results of the calculations completely reproduce the experimental data on stability of G-quadruplexes comparatively Watson-Crick B-DNA. It was discovered that combinations of non-canonical DNA structures were energetically more favorable than separated nitrogenous bases.

Thiol-induced nitric oxide donation mechanisms in substituted dinitrobenzofuroxans.

The goal of present work is the quantum chemical study of NO donation mechanism in dinitrobenzofuroxan aryl derivative. Mechanisms of its structural non-rigidity (1,3-N-oxidic and Boulton-Katritzky rearrangements) and minimum energy pathways of NO donation under the action of sulfanyl radical SH· were considered in details. DFT calculations were performed using B3LYP and UB3LYP functionals in the 6-311++G(d,p) basis set.

The stepwise Diels-Alder reaction of 4-nitrobenzodifuroxan with Danishefsky's diene.

The Diels-Alder reaction of 4-nitrobenzodifuroxan (NBDF) with 1-methoxy-3-trimethylsilyloxy-1,3-butadiene has been investigated experimentally and theoretically. Treatment of NBDF with excess diene in chloroform at room temperature was found to afford a single product that contained a carbonyl functionality. Based on an X-ray structure and NMR spectroscopic data, the product appeared to be a result of the hydrolysis of the OSiMe(3) moiety of the thermodynamically more stable endo [2+4] cycloadduct, characterized by a cis arrangement of the MeO and NO(2) functionalities.

N-[2-[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)amino]phenyl]-N-(5,7-dinitroquinolin-8-yl)-1-phenylmethanesulfonamide: the nature of intramolecular shortened contacts.

The title compound, C(36)H(35)N(5)O(7)S, is found to exist in a non-spirocyclic (ring-opened) form in the crystal, although equilibrium of ring-opened and ring-closed forms (or so-called ring-chain isomerization) is possible in solution. The 4-oxocyclohexa-2,5-diene ring has a flattened sofa conformation. The N.