oxyhyponitrite and diazeniumdiolate

Nitroxyl (HNO) demonstrates a diverse and unique biological profile compared to nitric oxide, a redox-related compound. Although numerous studies support the use of HNO as a therapeutic agent, the inherent chemical reactivity of HNO requires the use of donor molecules. Two general chemical strategies currently exist for HNO generation from nitrogen-containing molecules: (i) the disproportionation of hydroxylamine derivatives containing good leaving groups attached to the nitrogen atom and (ii) the decomposition of nitroso compounds (X-N=O, where X represents a good leaving group). This review summarizes the synthesis and structure, the HNO-releasing mechanisms, kinetics and by-product formation, and alternative reactions of six major groups of HNO donors: Angeli's salt, Piloty's acid and its derivatives, cyanamide, diazenium diolate-derived compounds, acyl nitroso compounds, and acyloxy nitroso compounds. A large body of work exists defining these six groups of HNO donors and the overall chemistry of each donor requires consideration in light of its ability to produce HNO. The increasing interest in HNO biology and the potential of HNO-based therapeutics presents exciting opportunities to further develop HNO donors as both research tools and potential treatments.

Topics: Azo Compounds; Cyanamide; Hydroxamic Acids; Molecular Structure; Nitrites; Nitrogen Oxides; Nitroso Compounds; Sulfonamides

Diazeniumdiolates, more commonly referred to as NONOates, have been extremely useful in the investigation of the biological effects of nitric oxide (NO) and related nitrogen oxides. The NONOate Angeli's salt (Na(2)N(2)O(3)) releases nitroxyl (HNO) under physiological conditions and exhibits unique cardiovascular features (i.e., positive inotropy/lusitropy) that may have relevance for pharmacological treatment of heart failure. In the search for new, organic-based compounds that release HNO, we examined isopropylamine NONOate (IPA/NO; Na[(CH(3))(2)CHNH(N(O)NO]), which is an adduct of NO and a primary amine. The chemical and pharmacological properties of IPA/NO were compared to those of Angeli's salt and a NO-producing NONOate, DEA/NO (Na[Et(2)NN(O)NO]), which is a secondary amine adduct. Under physiological conditions IPA/NO exhibited all the markers of HNO production (e.g., reductive nitrosylation, thiol reactivity, positive inotropy). These data suggest that primary amine NONOates may be useful as HNO donors in complement to the existing series of secondary amine NONOates, which are well-characterized NO donors.

Topics: Animals; Azo Compounds; Calcitonin Gene-Related Peptide; Cardiovascular System; Cell Survival; Cells, Cultured; Cricetinae; Cricetulus; Cyclic GMP; Dogs; Glutathione; Hemodynamics; Hydrazines; Lethal Dose 50; Male; Nitric Oxide Donors; Nitrites; Nitrogen Oxides; Uric Acid