Nucleophilic substitution reactions in m-nitrobenzylic substrates

1983 ◽  
Vol 36 (1) ◽  
pp. 81 ◽  
Author(s):  
SD Barker ◽  
RK Norris
Keyword(s):  
Nucleophilic Substitution ◽  
Radical Anion ◽  
Anion Radical ◽  
The Other ◽  
Radical Anions ◽  
Malonic Ester ◽  
Mechanism Of Formation ◽  
Substitution Reactions ◽  
Radical Process ◽  
Rule Out

The reaction of m-nitrobenzyl 2,4,6-trimethylbenzoate (11) with the salt (2) of 2-nitropropane, or the thiolate (16), gives moderate yields of substitution products [e.g.(3) or (17)]. However, the mechanism of formation of these products could not be definitively assigned. The m-nitrobenzyl chloride (12), on the other hand, was clearly demonstrated to undergo SRN1 substitution reactions with a variety of anions including the anion from the salt (2), thiolate ion from (16), azide from (22), the malononitrile anion from (20), and the malonic ester anion from (21). Inhibition and entrainment effects clearly rule out an alternative radical anion-radical process involving cage collapse. The occurrence of SRNl reactions in m-nitrobenzylic substrates adds support to a mechanism involving association of radicals with anions, and for dissociation of radical anions, which involves σ* and π* radical anions.

The other side of the superoxide radical anion: its ability to chemically repair DNA oxidized sites

2018 ◽  
Vol 54 (97) ◽  
pp. 13710-13713 ◽  
Author(s):  
Leonardo Muñoz-Rugeles ◽  
Annia Galano ◽  
Juan Raúl Alvarez-Idaboy
Keyword(s):  
Superoxide Anion ◽  
Radical Anion ◽  
Anion Radical ◽  
Superoxide Radical ◽  
Superoxide Anion Radical ◽  
The Other ◽  
Superoxide Radical Anion ◽  
Diffusion Controlled

Even though reaction of the superoxide anion radical/hydroperoxide radical could lead to oxidation of biomolecules, it can reduce oxidized DNA at diffusion controlled rates.

Modernism, Empiricism, and Rationalism

2016 ◽  
Vol 46 (1) ◽  
pp. 38-47
Author(s):  
Geoffrey Squires
Keyword(s):  
Twentieth Century ◽  
The Other ◽  
Modern Poetry ◽  
Philosophical Perspective ◽  
Irish Poetry ◽  
Dimensional Spectrum ◽  
Culture History ◽  
The World ◽  
The Impact ◽  
Rule Out

Modernism is usually defined historically as the composite movement at the beginning of the twentieth century which led to a radical break with what had gone before in literature and the other arts. Given the problems of the continuing use of the concept to cover subsequent writing, this essay proposes an alternative, philosophical perspective which explores the impact of rationalism (what we bring to the world) on the prevailing empiricism (what we take from the world) of modern poetry, which leads to a concern with consciousness rather than experience. This in turn involves a re-conceptualisation of the lyric or narrative I, of language itself as a phenomenon, and of other poetic themes such as nature, culture, history, and art. Against the background of the dominant empiricism of modern Irish poetry as presented in Crotty's anthology, the essay explores these ideas in terms of a small number of poets who may be considered modernist in various ways. This does not rule out modernist elements in some other poets and the initial distinction between a poetics of experience and one of consciousness is better seen as a multi-dimensional spectrum that requires further, more detailed analysis than is possible here.

Stability of radical anions derived from substituted 5-nitrofurans investigated by ESR spectroscopy

1985 ◽  
Vol 50 (7) ◽  
pp. 1594-1601 ◽  
Author(s):  
Jiří Klíma ◽  
Larisa Baumane ◽  
Janis Stradinš ◽  
Jiří Volke ◽  
Romualds Gavars
Keyword(s):  
Radical Anion ◽  
High Stability ◽  
Esr Spectroscopy ◽  
Reaction Path ◽  
Order Reaction ◽  
Second Order ◽  
Radical Anions ◽  
Second Order Reaction ◽  
Unpaired Electron Density ◽  
The Stability

It has been found that the decay in dimethylformamide and dimethylformamide-water mixtures of radical anions in five of the investigated 5-nitrofurans is governed by a second-order reaction. Only the decay of the radical anion generated from 5-nitro-2-furfural III may be described by an equation including parallel first- and second-order reactions; this behaviour is evidently caused by the relatively high stability of the corresponding dianion, this being an intermediate in the reaction path. The presence of a larger conjugated system in the substituent in position 2 results in a decrease of the unpaired electron density in the nitro group and, consequently, an increase in the stability of the corresponding radical anions.

scholarly journals EXPRESS: When Two Actors Perform Different Tasks: Still No Evidence for Shared Task-Sets in Joint Task Switching

2021 ◽  
pp. 174702182110315
Author(s):  
Motonori Yamaguchi ◽  
Husnain H. Shah ◽  
Bernhard Hommel
Keyword(s):  
Task Switching ◽  
The Other ◽  
Shared Task ◽  
Joint Condition ◽  
Task Instructions ◽  
Switch Costs ◽  
Joint Task ◽  
Task Sets ◽  
Rule Out

Two different variations of joint task switching led to different conclusions as to whether co-acting individuals share the same task-sets. The present study aimed at bridging this gap by replicating the version in which two actors performed two different tasks. Experiment 1 showed switch costs across two actors in a joint condition, which agreed with previous studies, but also yielded even larger switch costs in a solo condition, which contradicted the claim that actors represent an alternative task as their own when it is carried out by the co-actor but not when no one carries it out. Experiments 2 and 3 further examined switch costs in the solo condition with the aim to rule out possible influences of task instructions for and experiences with the other task that was not assigned to the actor. Before participants were instructed on the second of the two tasks, switch costs were still obtained without a co-actor when explicit task names (“COLOUR” and “SHAPE”) served as go/nogo signals (Experiment 2), but not when arbitrary symbols (“XXXX” and “​​​​”) served as go/nogo signals (Experiment 3). The results thus imply that switch costs depend on participants’ knowledge of task cues being assigned to two different tasks, but not on whether the other task is performed by a co-actor. These findings undermine the assumption that switch costs in the joint conditions reflect shared task-sets between co-actors in this procedure.

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