ABSTRACT
Thionitrates (R-SNO2) have been proposed as key intermediates in the biotransformation of organic nitrates that have been used for the clinical treatment of angina pectoris for over 100 years. It has been proposed and widely accepted that a thiol would react with an organic nitrate to afford a thionitrate intermediate. However, there has been no example of an experimental demonstration of this elementary chemical process in organic systems. Herein, we report that aryl- and primary-alkyl-substituted thionitrates were successfully synthesized by the reaction of the corresponding lithium thiolates with organic nitrates by taking advantage of cavity-shaped substituents. The structure of a primary-alkyl-substituted thionitrate was unambiguously established by X-ray crystallographic analysis.
Subject(s)
Chemistry Techniques, Synthetic , Nitrates/chemical synthesis , Nitric Oxide/chemistry , Sulfhydryl Compounds/chemical synthesis , Alkylation , Biotransformation , Crystallography, X-Ray , Kinetics , Models, ChemicalABSTRACT
Nitric oxide dimerization in gas phase and aromatic hosts (benzene) has been investigated with ab initio quantum mechanics. Using the (RO)MP2-aug-cc-pVDZ method, the computed bond dissociation energy (ON...NO) and geometry of (NO)2 in the gas phase are consistent with the reported spectroscopic data. A relatively strong interaction (-5.4 kcal/mol) between (NO)2 and benzene indicates that aromatic surrounding enhances the NO dimerization. Calculations on reactions of phosphine and methanethiol with NO and (NO)2 show that the dimer is much more reactive. This explains reactions of NO with phosphines and thiols.
Subject(s)
Benzene/chemistry , Nitric Oxide/chemistry , Dimerization , Kinetics , Models, Molecular , ThermodynamicsABSTRACT
Nitric oxide (NO) is a messenger molecule implicated in a number of physiological processes. Nitrosation of selenoproteins has been suggested as playing an important role in NO-mediated cellular functions such as the inactivation of glutathione peroxidase (GPx), but no chemical information about Se-nitrosated species has been available to date. Here a stable Se-nitrososelenol (RSeNO), a new class of NO derivative, was synthesized and fully characterized by X-ray crystallography and spectroscopic methods. This Se-nitrososelenol can be formed by direct transnitrosation from an S-nitrosothiol to a selenol, as is the case in the proposed mechanism for the NO-mediated inactivation of GPx.
