Amphiphilic Graft Copolymers for Time-Delayed Release of Hydrophobic Fragrances

Nagler, Frieda; Schiller, Christine; Kropf, Christian; Schacher, Felix H.

doi:10.1021/acsami.2c16205

Cited by 6 publications

(5 citation statements)

References 42 publications

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“…However, the more activated tris(trimethylsilyl)silane reacts efficiently with TEMPO through intermolecular HAT, and tetramethylpiperidine, derived from trapping of the silyl radical with TEMPO and subsequent cleavage of the N−O bond, was detected as the major product. 222,1090 The reaction of Si−H bonds with TEMPO to give TEMPO−Si adducts was also documented for Si (100) and Si (111) surfaces. 1091 In a recent report by the groups of Chen and Fan, the silylation of alcohols was described by using silanes and a catalytic amount of 4-NH 2 -TEMPO under argon atmosphere.…”

Section: Oxidation Of Silanes Stannanes and Germanesmentioning

confidence: 91%

“…Along with the already highlighted TEMPO, the PINO radical has found wide applications in organic synthesis, and addition to alkenes, hydrogen atom abstraction, , and oxidation reactions have been reported by using PINO (section ). Another prominent congener is SG1, , which is particularly important in the field of NMP. , TIPNO, which is accessible from phenyl tert -butyl nitrone (PBN), has been extensively used as a regulator in NMP , and also as a spin trapping reagent . Even though SG1 and TIPNO both bear a hydrogen atom in the α position to the NO moiety, both radicals can be isolated and do not disproportionate. , In general, nitroxides bearing α-H atoms − are less stable as they can readily disproportionate.…”

Section: Preparation Of Nitroxides and Selected Derivativesmentioning

confidence: 99%

“…Another prominent congener is SG1, 98,99 which is particularly important in the field of NMP. 49,100 TIPNO, which is accessible from phenyl tert-butyl nitrone (PBN), 101 has been extensively used as a regulator in NMP 49,102 and also as a spin trapping reagent. 103 Even though SG1 and TIPNO both bear a hydrogen atom in the α position to the NO moiety, both radicals can be isolated and do not disproportionate.…”

Section: Introduction and Historymentioning

confidence: 99%

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Organic Synthesis Using Nitroxides

Leifert

Studer

2023

Chem. Rev.

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Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R 1 R 2 N−O • . The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R 1 and R 2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R 1 R 2 N�O + ) or reduced to anions (R 1 R 2 N−O − ), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C−O bonds, allowing for the thermal generation of C radicals through reversible C−O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.

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Section: Oxidation Of Silanes Stannanes and Germanesmentioning

confidence: 91%

Section: Preparation Of Nitroxides and Selected Derivativesmentioning

confidence: 99%

Section: Introduction and Historymentioning

confidence: 99%

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Organic Synthesis Using Nitroxides

Leifert

Studer

2023

Chem. Rev.

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“…Die ultraschallaktivierte Auffaltung und Bindungsspaltung dieser Aptamere setzte den Wirkstoff Doxorubicin frei. 35) Darüber hinaus entwickelten einige Gruppen Polymermaterialien, die potenziell für Wirkstofftransport und -freisetzung nützlich sind: Schacher und Mitarbeitende synthetisierten amphiphile Pfropfcopolymere, um Duftstoffe freizusetzen, 36) Comunian und Team erforschten die Koazervatkomplexbildung von Gummi arabicum und Erbsenprotein, 37) Zeiniger und Team zeigten die chemotaktische Bewegung von Janus-Tröpfchen 38) und Appelhans, Gallei und Mitarbeitende redox-und pH-responsive Polymersome. 39)…”

Section: Strukturpolymereunclassified

Trendbericht: Makromolekulare Chemie 2023

Göstl

2023

Nachr Chem

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“…24,27 Co-polymers of PDha have either been prepared by ATRP of t BAMA with polymeric halogenides and subsequent deprotection of the ionizable moieites [27][28][29][30] or by post-modification of a fraction of the amino functions in the homopolymer. [31][32][33] In the last years, the Schacher group has focussed on exploiting the co-existence of positive and negative charges within PDha for various applications. Magnetic nanoparticles (MNPs) coated with PDha 34 were shown to adsorb and desorb polyelectrolyte model cargo by electrostatic interaction depending on the pH value of the surrounding medium.…”

Section: Introductionmentioning

confidence: 99%