selective substitution
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Author(s):  
James Higham ◽  
Debbie Hopkins ◽  
Caroline Orchiston

AbstractAcademics are part of a small minority that are responsible for disproportionate air travel emissions. Responding to high aviation emissions requires that the complexities of academic air travel practices are understood in specific geographical and institutional contexts. This chapter addresses the work-sociology of academic aeromobility in the context of the global periphery. We report on a programme of interviews conducted prior to COVID-19 with academics at the University of Otago (Aotearoa/New Zealand), where the aeromobility practices of academics are uniquely shaped by extreme geographical distance. Our empirical contribution is presented in the four themes that emerged from our analysis: complex drivers; selective substitution; ‘Don’t weaken me!’ and assorted scalar accountabilities. We then discuss aspects of resistance to change but also avenues of opportunity to reimagine academic air travel practices, which have been accelerated by the COVID-19 pandemic. We specifically address the emergence of a post-COVID ‘new normal’ and conclude with the urgent need for collective action that is coordinated among individual academics, institutions, disciplinary associations and conference organisers. Entrenching the ‘new normal’ will be critical to resolving the unsustainable aeromobilities of academics and institutions that are globally distant.


Synlett ◽  
2021 ◽  
Author(s):  
Kozo Toyota ◽  
Shinichi Mikami ◽  
Akihiro Matsuo ◽  
Eunsang Kwon

AbstractFour isomers of 4,7′-bibenzothiophene scaffolds bearing two different halogen (Br, Cl) and triisopropylsilyl substituents have been synthesized from the two multihalobenzo[b]thiophenes via iodoselective Miyaura borylation reaction using potassium benzoate as a base. Further investigation into the reactivity of 4,7′-bibenzothiophenes in substitution reaction, Suzuki–Miyaura cross-coupling reaction, and C–H direct arylation reaction revealed that tetrasubstituted 4,7′-bibenzothiophenes can be synthesized site- (chemo-) selectively, which are promising novel components for molecular architecture.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Shiori Suzuki ◽  
Tadahisa Iwata

AbstractKraft lignin is a valuable aromatic renewable resource that is discharged in large quantities during the kraft pulping process. In this study, kraft lignin derivatives with improved solubility and thermal properties were prepared by a facile chemical modification of the aliphatic hydroxy (R-OH) group in kraft lignin with various ester groups. Kraft lignin was subjected to homogeneous transesterification with vinyl esters as acyl donors using an ionic liquid as a green solvent and catalyst. The selective introduction of acyl groups into the R-OH group was confirmed by nuclear magnetic resonance (NMR) spectroscopy, and it was estimated that approximately 90% of the R-OH group was converted whereas more than 80% of the aromatic hydroxy (Ar-OH) group was retained. The R-OH-selective introduction of long-chain acyl groups of more than six carbons successfully provided superior solubility in common low-boiling solvents, such as chloroform and tetrahydrofuran, and sufficient heat-meltability to be molded into films by hot-pressing. All the kraft lignin derivatives showed high glass transition temperatures of over 100 °C, indicating their potential to be heat-resistant materials. The kraft lignin derivatives, in which only the R-OH group was acylated, retain their inherently rich Ar-OH groups and thus, can be applied as desirable precursors in a wide range of further chemical treatments for functional polymer materials.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1365
Author(s):  
Kotaro Kikushima ◽  
Haruka Koyama ◽  
Kazuki Kodama ◽  
Toshifumi Dohi

Nucleophilic aromatic substitution (SNAr) reactions can provide metal-free access to synthesize monosubstituted aromatic compounds. We developed efficient SNAr conditions for p-selective substitution of polyfluoroarenes with phenothiazine in the presence of a mild base to afford the corresponding 10-phenylphenothiazine (PTH) derivatives. The resulting polyfluoroarene-bearing PTH derivatives were subjected to a second SNAr reaction to generate highly functionalized PTH derivatives with potential applicability as photocatalysts for the reduction of carbon–halogen bonds.


Author(s):  
Kotaro Kikushima ◽  
Haruka Koyama ◽  
Kazuki Kodama ◽  
Toshifumi Dohi

Nucleophilic aromatic substitution (SNAr) reactions can provide metal-free access to synthesize mono-substituted aromatic compounds. We have developed efficient SNAr conditions for p-selective substitution of polyfluoroarenes with phenothiazine in the presence of a mild base to afford the corresponding 10-phenylphenothiazine (PTH) derivatives. The resulting polyfluoroarene-bearing PTH derivatives were subjected to a second SNAr reaction to generate highly functionalized PTH derivatives with potential applicability as photocatalysts for the reduction of carbon–halogen bonds.


2020 ◽  
Vol 3 (12) ◽  
pp. 1329-1340
Author(s):  
Mariya Kalapsazova ◽  
Pavel Markov ◽  
Krassimir Kostov ◽  
Ekaterina Zhecheva ◽  
Diana Nihtianova ◽  
...  

2020 ◽  
Vol 89 (8) ◽  
pp. 083701 ◽  
Author(s):  
Yasuki Kishimoto ◽  
Deepa Kasinathan ◽  
Hiroshi Yasuoka ◽  
Kristian Bader ◽  
Peter Gille ◽  
...  

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