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840 results on '"Parrish, Damon A."'

6. Investigation into a Conformationally Locked (Z)-Azidoxime

Author

Cleveland, Alexander H., Davis, Jack V., Imler, Gregory H., Byrd, Edward F. C., Snyder, Christopher J., Chavez, David E., and Parrish, Damon A.

Abstract

High nitrogen compounds find wide use in the development of new propellants and explosives as well as pharmaceutical chemistry as bioisosteres, bacterial stains, and antifungal agents. A class of underexplored high-nitrogen materials includes azidoximes and their 1-hydroxytetrazole isomers. Azidoximes possess an energetic azide group and are quite sensitive to impact, spark, and friction. Therefore, these materials are generated in situ and cyclized under mild acidic conditions to their 1-hydroxytetrazole isomers. Recently, we synthesized a novel 1,2,4-triazine-derived azidoxime; however, upon subjecting this material to established cyclization conditions, no reaction was observed, even after prolonged reaction times with heating. Additional 1,2,4-triazine-derived azidoximes also displayed a similar lack of reactivities. This observation led us to probe the reactivity of these materials with both a DFT investigation and crystallographically based electrostatic potential mapping. In all, the lack of reactivity toward cyclization was found to be due to an inability of 1,2,4-triazine-based azidoximes to isomerize into the reactive (E)-conformation, requiring an activation energy of 26.4 kcal mol–1.

Published
2023
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10. A study of the structure–activity relationship of GABA A–benzodiazepine receptor bivalent ligands by conformational analysis with low temperature NMR and X-ray analysis

Author

Han, Dongmei, Holger Försterling, F., Li, Xiaoyan, Deschamps, Jeffrey R., Parrish, Damon, Cao, Hui, Rallapalli, Sundari, Clayton, Terry, Teng, Yun, Majumder, Samarpan, Sankar, Subramaniam, Roth, Bryan L., Sieghart, Werner, Furtmuller, Roman, Rowlett, James K., Weed, Michael R., and Cook, James M.

Published
2008
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12. Sculpting the bicyclo[3.1.0]hexane template of carbocyclic nucleosides to improve recognition by herpes thymidine kinase

Author

Comin, Maria J., Agbaria, Riad, Ben-Kasus, Tsipi, Huleihel, Mahmoud, Liao, Chenzhong, Sun, Guangyu, Parrish, Damon A., and Marquez, Victor E.

Subjects
Hexane -- Chemical properties, Carbocyclic compounds -- Structure, Carbocyclic compounds -- Chemical properties, Herpes simplex virus -- Genetic aspects, Herpes simplex virus -- Research, Phosphotransferases -- Structure, Phosphotransferases -- Chemical properties, Thymidine -- Structure, Thymidine -- Chemical properties, Chemistry
Abstract

The study describes the design, synthesis and phosphorylation pattern of the new bicyclo[3.1.0]hexane template that exhibits highly strong and increased chemical and enzymatic stability due to the absence of a true glycosyl bond. The template is found to be extremely rigid that makes it useful for sculpting other carbocyclic nucleosides, which also makes it easier to interact with the herpes simplex thymidine kinase.

Published
2007

14. Experimental charge density study of estrogens: 17[beta]-estradiol-urea

Author

Parrish, Damon, Zhurova, Elizabeth A., and Kirschbaum, Kristin

Subjects
Estradiol -- Chemical properties, Estrogen -- Chemical properties, Urea -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

The charge density analysis of the series of 17[beta]-estradiol urea using optical coordinate system and slow, initially constrained refinement is presented. It is observed that the oxygen atoms seem to be near to [sp.sup.3] in shape, demonstrating two consistent, distinct lone pairs despite varying chemical environments.

Published
2006

16. Chemistry of the diazeniumdiolates. O-versus N-alkylation of the RNH[N(O)NO](super -) ion

Author

Saavedra, Joseph E., Bohle, D. Scott, Smith, Kamilah N., George, Clifford, Deschamps, Jeffrey R., Parrish, Damon, Ivanic, Joseph, Yan-Ni Wang, Citro, Michael L., and Keefer, Larry K.

Subjects
Chemical bonds -- Research, Oxygen -- Chemical properties, Nitrogen -- Chemical properties, Methylation -- Methods, Chemistry
Abstract

Monomethylation of the potentially ambident RNH[N(O)NO](super -) ion (R=isoprophyl or cyclohexyl) is shown to occur at the terminal oxygen to yield the novel diazeniumdiolate structural unit, RNHN-(O)=NOMe. The evidence for extensive delocalization and associated changes in bond order on ionizing RNHN(O)-NOR' are found in density functional theory calculation using Gaussian 03 with B2LYP/6-311++G** basis sets.

Published
2004

24. Intramolecular coupling reactions of allylic thioesters with diene iron tricarbonyl systems

Author

Pearson, Anthony J., Alimardanov, Asaf, Pinkerton, A. Alan, and Parrish, Damon A.

Subjects
Amides -- Research, Chemical reactions -- Research, Esters -- Research, Ring formation (Chemistry) -- Research, Sulfur -- Research, Biological sciences, Chemistry
Abstract

A study was conducted to analyze the ring opening of the lactam system in intramolecular coupling reactions and the use of thioesters during the cyclization reaction and their associated ring opening and sulfur extrusion. Carboxylic acid was reacted in distilled CH2Cl2 using a round-bottom flash under an argon environment. Results indicated that the complexes were significantly less reactive toward the metal-assisted cyclization than amide analogues.

Published
1998

25. Correlation of a solution conformational change between mercuric chloride complexes of Tris((2-(6-methylpyridyl))metheyl)amine with x-ray crystallographic structures

Author

Bebout, Deborah C., Bush, James F. II, Crahan, Kathleen K., Kastner, Margaret E., and Parrish, Damon a.

Subjects
Mercuric oxide -- Observations, X-ray crystallography -- Usage, Chemistry
Abstract

The complexation of HgC1(sub2) by the ligand tris((6-methyl-2-pyridyl)methyl)amine (TLA) in acetonitrile was investigated using solution state NMR and x-ray crystallography. This system can monitor a simple conformational change of Hg(II)-bound ligand, and the transformation was fully observable by NMR. The NMR spectra were consistent with the formation of complexes having average 3-fold symmetry.

Published
1998

26. Characterization of mercury(II) complexes of bis((2-pyridyl)methyl)amine by X-ray crystallography and NMR spectroscopy

Author

Bebout, Deborah C., DeLanoy, Anne E., Ehmann, David E., Kastner, Margaret E., Parrish, Damon A., and Butcher, Raymond J.

Subjects
Complex compounds -- Spectra, Coordination compounds -- Research, Mercury compounds -- Research, Chemistry
Abstract

Solution-state nuclear magnetic resonance spectroscopy and X-ray crystallography were used to examine the complexation of mercury(II) complexes by the dipodal ligand bis((2-pyridyl)methyl)amine. Detection of 1H199Hg satellites, rarely observed for mercury coordination compounds, is shown to facilitate the analysis of the equilibria between Hg(II) and a tridentate ligand. Large differences in J(1H199Hg) involving related ligand protons in the two complexes were noted.

Published
1998

27. Preparation of mercury(II) complexes of tris((2-pyridyl)methyl)amine and characterization by X-ray crystallography and NMR spectroscopy

Author

Bebout, Deborah C., Ehmann, David D., Trinidad, Jonathan C., Crahan, Kathleen K., Kastner, Margaret E., and Parrish, Damon A.

Subjects
Nuclear magnetic resonance spectroscopy -- Usage, Crystallography -- Usage, Mercury -- Observations, Chemistry
Abstract

Solution state NMR and X-ray crystallography was used to investigate the complexation of Hg(II) by the tripodal ligand tris((2-pyridyl)methyl)amine (TMPA). Conditions for slow exchange of Hg(II) in the solution states were established, allowing observation of super1Hsuper199Hg and super13Csuper199Hg couplings by NMR. The TMPA complexes were compared with other TMPA metal ion complexes.

Published
1997

32. Finding furoxan rings

Author

Yu, Qiong, primary, Chinnam, Ajay Kumar, additional, Yin, Ping, additional, Imler, Gregory H., additional, Parrish, Damon A., additional, and Shreeve, Jean'ne M., additional

Published
2020
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42. New Generation Agent Defeat Weapons: Energetic N, N′‐Ethylene‐Bridged Polyiodoazoles

Author

Zhao, Gang, Kumar, Dheeraj, He, Chunlin, Hooper, Joseph P., Imler, Gregory H., Parrish, Damon A., Shreeve, Jean'ne M., and Physics

Subjects
energetic materials, polyiodoazoles, heterocycles, agent defeat weapons, N′-ethylene-bridged
Abstract

The article of record as published may be found at https://doi.org/10.1002/chem.201704798 Sodium salts of iodine-rich pyrazole and imida- zole with 1-(2-bromoethyl)-5-aminotetrazole are useful precursors for energetic N,N’-ethylene-bridged polyiodoa- zoles. Compounds 1–3 were characterized with IR, and 1H and 13C NMR spectroscopy as well as elemental analyses. The molecular structures of 1 and 2 were confirmed by using single crystal X-ray diffraction. Heats of formation were calculated using Gaussian 03 and detonation proper- ties and biocidal efficiency were calculated with CHEE- TAH 7. The decomposition products of 1–3 destroy microbes more effectively than some previously reported biocides since the thermal decomposition occurs at below 4008C without addition of oxidizer or combustion adjuvant. Office of Naval Research Defense Threat Reduction Agency M.J. Murdock Charitable Trust Financial support of the Office of Naval Research (N00014-16- 1-2089), the Defense Threat Reduction Agency (HDTRA 1-15-1- 0028), and the M. J. Murdock Charitable Trust (No. 2014120) for funds supporting the purchase of a 500 MHz NMR are gratefully acknowledged.

Published
2017

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