نتایج جستجو برای: nitrones
تعداد نتایج: 453 فیلتر نتایج به سال:
The National Institute on Aging's Interventions Testing Program was established to evaluate agents that are purported to increase lifespan and delay the appearance of age-related disease in genetically heterogeneous mice. Up to five compounds are added to the study each year and each compound is tested at three test sites (The Jackson Laboratory, University of Michigan, and University of Texas ...
The novel bicyclic pentadentate ligand 5-methyl-1,5,9,24,25-pentaazapentacyclo[7.7.7.5.5]pentacosane11,13,15,18(25),20,22-hexene (L1) has been synthesized. Because of its cross-bridged topology it exhibits a relatively rigid preorganized conformation especially appropriate to complex formation, as shown by the crystal structure of the monoprotonated ligand salt, HL1ClH2O [orthorhombic, P212121,...
Reactivities of Superoxide and Hydroperoxyl Radicals with Disubstituted Cyclic Nitrones: A DFT Study
[structure: see text] The total synthesis of the putative structure of the Stemona alkaloid stemonidine has been completed. The key transformations include a 1,3-dipolar cycloaddition of a chiral nitrone derived from (S)-prolinol and a spirolactonization process involving the generation of the critical stereocenter. The NMR data of the synthetic material do not match those reported for the natu...
The title compound, C(19)H(13)N(5)O(3), can be obtained from the corresponding α-amido-α-amino-nitrone in a reaction with biphenyl-2,2'-diamine. The amido-amidine core has distinctive geometrical parameters including: an outstandingly long Csp(2)-Csp(2) single bond of 1.5276 (13) Å and an amidine N-C-N angle of 130.55 (9)°. Intra-molecular N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds occur. In the cry...
The 2-Aza-Cope rearrangement of γ-alkenyl nitrones is a rare example of the neutral thermal 2-aza-Cope process that usually takes place with cationic species. During the rearrangement, a redistribution of bonds and electronic density occurs in one kinetic step. However, the introduction of substituents with different steric requirements and electronic features might alter the activation energie...
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