1. Reactions of Nitric Oxide with -Hydroxylimino Esters
Elayna Mahone and Dr. Navamoney Arulsamy
Department of Chemistry
University of Wyoming

2. Outline Background and Significance Expected synthesis
Results and mechanisms
Spectra
Further research
Acknowledgements

3. Background and Significance
Nitric oxide (NO) donor pro-drugs
Physiological roles
Alcoholism deterrent (HNO)
Cardiovascular disease cure
Versatile
NO and HNO releasing
Explosives
Decomposition properties

4. Dimeric Addition of NO
Formation of sydnone-N-oxide and diazeniumdiolate products
Dimeric addition; biological effect different with a lot or little NO-> 3 & 4 go trans

5. Expected Products from -Ketoximino Esters
Reaction between -ketoxime such as methyl acetoacetoxime (R = Me) and nitric oxide
Treat acidic CH2 group containing compounds with a base, cool, and then de-gas, treat with NO
NO reactive with air

6. Synthesis of -Ketoximino Esters
Oxime substrates not commercially available
Generated in situ, not isolated
Literature used pyridine rather than methanol

7. Results
Generated -ketoximes to form two unexpected products under two different methods
Potassium 4-acetyltriazolium-1,2,3-triolate
These two products were very different because their UV-Visible spectra were different. Sydnone products have two peaks, at ~230 and 300 nm. Diazeniumdiolate products have a single peak at 245 (one diazeniumdiolate, 258 (two), or 265 nm (three).
Potassium 3-ethyl-5-isoxazolone-4-diazeniumdiolate

9. Product Spectra MeCOC2N3O3K2 UV-Vis
UV-Vis data were somewhat similar to sydnone-oxide UV-Vis, but these spectra had one additional peak; more data needed  NMR

10. MeCOC2N3O3K2 H1 NMR in D2O/DSS
2.402 acetyl group

11. MeCOC2N3O3K2 C13 NMR in D2O/DSS
DSS reference (aqueous solutions); NMR spectra somewhat consistent with expected sydnone, but already known in literature, numbers are different (peak positions not identical)

12. MeCOC2N3O3K2 X-ray structure
Bond Distances (Å)
C(3)-N(1) (7)
C(3)-C(4) (8)
N(1)-N(2) (7)
N(2)-O(4) (6)
N(2)-N(3) (6)
N(3)-O(3) (6)
N(3)-C(4) (7)
C(4)-O(2) (6)
This structure is previously unknown, new compound not in literature; aromaticity drives this condensation; Bonds are neither single nor double but delocalized.

13. EtCOC2N3O3K2
UV-Vis

14. EtCOC2N3O3K2 H1 NMR in D2O/DSS
3.34 methanol impurity

15. EtCOC2N3O3K2 C13 NMR in D2O/DSS

16. EtCOC2N3O3K2 H coupled C13 NMR

17. EtC3HNO2N2O2K
UV-Vis

18. EtC3HNO2N2O2K H1 in D2O/DSS

19. EtC3HNO2N2O2K C13 in D2O/DSS
Lower two peaks from ethyl; one triplet, two singlets at high ppm values  five different carbons present; isoxazolone ring present; not deuterium decoupled, one D can split a carbon into a triplet

20. Mechanism
diazeniumdiolate

21. Mechanism
Sydnone; Immediate, K no time to react before NO, N electron rich, does not go where acidic hydrogen

22. Further Research EPR (electron paramagnetic resonance)
Release of NO
TGA/DSC (Thermogravimetric and Differential Scanning Calorimetry)
Thermal decomposition properties
Decomposition mechanism
Nitric oxide trap; can be explosive, TGA used to help study how decomposing

23. Acknowledgements Honors Program, University of Wyoming
Faculty Grant-In Aid, University of Wyoming
Department of Chemistry, University of Wyoming