Nitroxyl

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Nitroxyl
Ball and stick model of nitroxyl
Identifiers
CAS number 14332-28-6
PubChem 945
ChemSpider 920 YesY
MeSH Nitroxyl
ChEMBL CHEMBL1200689 YesY
Jmol-3D images Image 1
Properties
Molecular formula HNO
Molar mass 31.01 g mol−1
log P 0.74
Structure
Coordination
geometry
Digonal
Molecular shape Dihedral
Thermochemistry
Specific
heat capacity
C
33.88 J K-1 mol-1
Std molar
entropy
So298
220.91 J K-1 mol-1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Nitroxyl is the common chemical name for HNO, being azanone its IUPAC name.1 It is well known in the gas phase.2 In aqueous solution it acts as an acid with the conjugate base NO, (pKa = 11.4).3 NO is the reduced form of nitric oxide (NO) and is isoelectronic with dioxygen. Nitroxyl can be formed as a reaction intermediate.
Nitroxyl is very reactive towards nucleophiles (especially thiols) and quickly dimerizes to hyponitrous acid, H2N2O2, which is then dehydrated to nitrous oxide N2O. Therefore, HNO is generally prepared in situ for example with the compounds such as Angeli’s salt (Na2N2O3) and Piloty’s acid (PhSO2NHOH) when it is needed.

Nitroxyl shows potential in the treatment of heart failure and ongoing research is focused on finding new nitroxyl donors. In one study 4 such donor is prepared by organic oxidation of cyclohexanone oxime with lead tetraacetate to 1-nitrosocyclohexyl acetate:

Nitrosocyclohexyl acetate

This compound can be hydrolyzed under basic conditions in a phosphate buffer to nitroxyl HNO, acetic acid and cyclohexanone.

Other studies that have been conducted on HNO precursors include those from Nagasawa et al.5 in which Piloty's acid is derivatized and produces HNO upon thermal decomposition. Other notable studies on the production of HNO come from Toscano et al.6 in which cycloadducts of acyl nitroso species (which are known to decompose via hydrolysis to HNO and acyl acid) are synthesized. Upon photolysis these compounds release the acyl nitroso species which then further decomposes.

References

  1. ^ Nitroxyl (azanone) trapping by metalloporphyrinsDoctorovich, F., Bikiel, D., Pellegrino, J., Suárez, S.A., Larsen, A., Martí, M.A.2011Coordination Chemistry Reviews255(23-24), pp. 2764-2784
  2. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0080379419. 
  3. ^ Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
  4. ^ Hydrolysis of Acyloxy Nitroso Compounds Yields Nitroxyl (HNO) Xin Sha, T. Scott Isbell, Rakesh P. Patel, Cynthia S. Day, and S. Bruce King J. Am. Chem. Soc.; 2006; 128(30) pp 9687 - 9692; (Article) doi: 10.1021/ja062365a
  5. ^ Prodrugs of Nitroxyl as Potential Aldehyde Dehydrogenase Inhibitors vis-a-vis Vascular Smooth Muscle Relaxants Nagasawa, H. T.; Kawle, S. P.; Elberling, J. A.; DeMaster, E. G.; Fukuto, J. M. J. Med. Chem., 38, 1865-1871. doi:10.1021/jm00011a005
  6. ^ Cohen, A. D.; Zeng, B.-B.; King, S. B.; Toscano, J. P. J. Am. Chem. Soc. 2003, 125, 1444-1445.doi:10.1021/ja028978e







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