Preparation of a thallium(I) diazotate.  Structure, physicochemical characterization, and conversion to novel N-nitroso compounds

Keefer, Larry K.; Wang, Shui Mei.; Anjo, Takako; Fanning, James C.; Day, Cyn­thia S.

doi:10.1021/ja00217a018

Cited by 14 publications

(17 citation statements)

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“…The nitrosamine moiety is on the same plane as the original methylhydrazine residue (Figure 5). The dihedral angle between the plane created by the methylhydrazine moiety and that of the –N(NO) plane is 0.6°, similar to that found in the crystal structure of the potassium11 and thallium12 methyl(nitroso)amide salts. The nitroso group N–O distance (1.284(2) Å), although longer than for highly conjugated tetrazole‐based systems36 or potassium11 and thallium12 methyl(nitroso)amide salt, is similar to those found in nitrosoanilines 37.…”

Section: Resultssupporting

confidence: 79%

“…To obtain a better understanding of the electron density in the structure of the [CH 3 N 2 O] – anion and that of 3 , an NBO analysis was performed on the optimized structures of the cis ‐ and trans ‐ [CH 3 N 2 O] – anion and that of 3 (Table 3). For compound 3 , the computed (gas phase) B3LYP bond lengths and angles agree nicely with the results of the crystal structure measurements (see discussion below), however, there is a lack of agreement between the computed values for the cis ‐ and trans ‐[CH 3 N 2 O] – anions and those previously measured for trans ‐K[CH 3 N 2 O]11 and cis ‐Tl[CH 3 N 2 O] 12. This disagreement can be understood by looking at the N‐O distances in the latter two compounds, which are unusually long.…”

Section: Resultssupporting

confidence: 74%

“…The potassium salt was synthesized later on from a p ‐MeC 6 H 4 SO 2 N(NO)Me solution in dry ether, which was added rapidly to potassium metal in absolute ethanol10 or, more conveniently, from reaction of potassium ethoxide with an N ‐methyl‐ N ‐nitroso‐ N ‐acyl derivative. [10b, 11] Finally, the sodium and thallium salts were synthesized by the reaction between monomethylamine with n ‐buthylnitrite in the presence of a suitable metal ethoxide (Na or Ta) 12. Interestingly, the crystal structure of the potassium salt shows a cis ‐arrangement, [10b, 11] which is in contrast with the trans ‐geometry found later on for the thallium salt 12…”

Section: Introductionmentioning

confidence: 99%

“…[10b, 11] Finally, the sodium and thallium salts were synthesized by the reaction between monomethylamine with n ‐buthylnitrite in the presence of a suitable metal ethoxide (Na or Ta) 12. Interestingly, the crystal structure of the potassium salt shows a cis ‐arrangement, [10b, 11] which is in contrast with the trans ‐geometry found later on for the thallium salt 12…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Selection of Flexible Proteins for Structure‐Based Drug Design: Backbone and Side Chain Movements in p38 MAPK

2008

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Receptor rearrangement upon ligand binding (induced fit) is a major stumbling block in docking and virtual screening. Even though numerous studies have stressed the importance of including protein flexibility in ligand docking, currently available methods provide only a partial solution to the problem. Most of these methods, being computer intensive, are often impractical to use in actual drug discovery settings. We had earlier shown that ligand-induced receptor side-chain conformational changes could be modeled statistically using data on known receptor-ligand complexes. In this paper, we show that a similar approach can be used to model more complex changes like backbone flips and loop movements. We have used p38 MAPK as a test case and have shown that a few simple structural features of ligands are sufficient to predict the induced variation in receptor conformations. Rigorous validation, both by internal resampling methods and on an external test set, corroborates this finding and demonstrates the robustness of the models. We have also compared our results with those from an earlier molecular dynamics simulation study on DFG loop conformations of p38 MAPK, and found that the results matched in the two cases. Our statistical approach enables one to predict the final ligand-induced conformation of the active site of a protein, based on a few ligand properties, prior to docking the ligand. We can do this without having to trace the step-by-step process by which this state is arrived at (as in molecular dynamics simulations), thereby drastically reducing computational effort.

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Section: Resultssupporting

confidence: 79%

Section: Resultssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling and Selection of Flexible Proteins for Structure‐Based Drug Design: Backbone and Side Chain Movements in p38 MAPK

2008

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“…9) on reaction with alkylating agents. 49 A sample of IPA/NO whose reactivity had dramatically changed after nine months of storage at −10°C but that was nevertheless visually indistinguishable from the freshly isolated pure material was slurried as the dry powder (51 mg) in 1 mL of iodomethane. After standing at room temperature for 3 d in a dry nitrogen atmosphere, the solid was filtered off, the filtrate was evaporated, and the residue was taken up in dichloromethane for analysis by gas chromatography.…”

Section: Resultsmentioning

confidence: 99%

HNO and NO Release from a Primary Amine-Based Diazeniumdiolate As a Function of pH

et al. 2011

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The growing evidence that nitroxyl (HNO) has a rich pharmacological potential that differs from that of nitric oxide (NO) has intensified interest in HNO donors. Recently, the diazeniumdiolate (NONOate) based on isopropylamine (IPA/NO; Na[(CH3)2CHNH(N(O)NO)]) was demonstrated to function under physiological conditions as an organic analogue to the commonly used HNO donor Angeli’s salt (Na2N2O3). The decomposition mechanism of Angeli’s salt is dependent on pH, with transition from an HNO to an NO donor occurring abruptly near pH 3. Here, pH is shown to also affect product formation from IPA/NO. Chemical analysis of HNO and NO production led to refinement of an earlier, quantum mechanically based prediction of the pH-dependent decomposition mechanisms of primary amine NONOates such as IPA/NO. Under basic conditions, the amine proton of IPA/NO is able to initiate decomposition to HNO by tautomerization to the nitroso nitrogen (N2). At lower pH, protonation activates a competing pathway to NO production. At pH 8, the donor properties of IPA/NO and Angeli’s salt are demonstrated to be comparable, suggesting that at or above this pH, IPA/NO is primarily an HNO donor. Below pH 5, NO is the major product, while IPA/NO functions as a dual donor of HNO and NO at intermediate pH. This pH-dependent variability in product formation may prove useful in examination of the chemistry of NO and HNO. Furthermore, primary amine NONOates may serve as a tunable class of nitrogen oxide donor.

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4,5‐Dihydro‐1,2,3‐oxadiazole: A Very Elusive Key Intermediate in Various Important Chemical Transformations

Banert

Singh

Fiedler

et al. 2015

Chemistry A European J

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4,5-Dihydro-1,2,3-oxadiazoles are postulated to be key intermediates in the industrial synthesis of ketones from alkenes, in the alkylation of DNA in vivo, and in the decomposition of N-nitrosoureas; they are also a subject of great interest for theoretical chemists. In the presented report, the formation of 4,5-dihydro-1,2,3-oxadiazole and the subsequent decay into secondary products have been studied by NMR monitoring analysis. The elusive properties evading characterization have now been confirmed by (1) H, (13) C, and (15) N NMR spectroscopy, and relevant 2D experiments at very low temperatures. Our experiments with suitably substituted N-nitrosoureas using thallium(I) alkoxides as bases under apolar conditions answer important questions on the existence and the secondary products of 4,5-dihydro-1,2,3-oxadiazole.

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Preparation of a thallium(I) diazotate. Structure, physicochemical characterization, and conversion to novel N-nitroso compounds

Cited by 14 publications

References 0 publications

Modeling and Selection of Flexible Proteins for Structure‐Based Drug Design: Backbone and Side Chain Movements in p38 MAPK

Modeling and Selection of Flexible Proteins for Structure‐Based Drug Design: Backbone and Side Chain Movements in p38 MAPK

HNO and NO Release from a Primary Amine-Based Diazeniumdiolate As a Function of pH

4,5‐Dihydro‐1,2,3‐oxadiazole: A Very Elusive Key Intermediate in Various Important Chemical Transformations

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