Related Experiment Video
Updated: Jun 18, 2025
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
05:15
Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
6.8K
Spirocyclic Pyrrolidinyl Nitroxides with Exo-Methylene Substituents
Mateusz P Sowiński1, Anna-Luisa Warnke1, Bjarte A Lund1
1Department of Chemistry, UiT The Arctic University of Norway, Tromsø, 9037, Norway.
Chempluschem
|July 29, 2024
Summary
Researchers developed new nitroxide radicals for biological studies. These stable organic radicals offer enhanced properties for observing biomolecular structure and dynamics, even at high temperatures.
Area of Science:
- Organic Chemistry
- Biophysical Chemistry
- Spectroscopy
Background:
- Nitroxides are stable organic radicals used as probes and polarizing agents in spectroscopy.
- Key properties for biological applications include resistance to degradation and favorable electron spin relaxation.
- Molecular structure and conformation significantly impact nitroxide performance.
Purpose of the Study:
- To synthesize and characterize novel nitroxides based on a spirocyclic pyrrolidine scaffold with an exocyclic methylene substituent.
- To evaluate the conformational preferences, stability, and electron spin relaxation properties of these new nitroxides.
Main Methods:
- Synthesis of novel spirocyclic pyrrolidine nitroxides.
- X-ray crystallography for conformational analysis.
- Electron paramagnetic resonance (EPR) spectroscopy to assess stability and relaxation.
- Cyclic voltammetry (CV) for kinetic and thermodynamic stability studies.
Main Results:
- Successful synthesis of the first nitroxides featuring a spirocyclic pyrrolidine scaffold with an exocyclic methylene group.
- Detailed conformational analysis via X-ray crystallography, including in crystalline sponges.
- Demonstrated kinetic and thermodynamic stability towards reduction using EPR and CV.
- Characterized electron spin relaxation properties relevant for spectroscopic applications.
Conclusions:
- The new family of nitroxides exhibits promising stability and tunable electronic properties.
- These multifunctionalized nitroxides are suitable for biological applications, including at elevated temperatures.
- The spirocyclic pyrrolidine scaffold offers a versatile platform for designing advanced spin probes and polarizing agents.
More Related Videos
06:18Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate
Published on: April 24, 2018
8.4K
07:30A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
Published on: January 21, 2020
8.1K
Related Concept Videos
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
6.0K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
6.0K
01:13meta-Directing Deactivators: –NO2, –CN, –CHO, –CO2R, –COR, –CO2H
5.5K
All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
5.5K
02:38Structure and Nomenclature of Epoxides
6.4K
Cyclic ethers are heterocyclic compounds with an oxygen atom in the ring along with carbon atoms. They are named depending on the number of carbon atoms present in their ring system. Cyclic ethers with a three-membered ring system are called “oxirane”, four-membered ring systems as “oxetane”, five-membered ring systems as “oxolane”, and six-membered ring systems as “oxane”. The cyclic structure of these rings imposes angle strain, and this strain...
6.4K
02:26Base-Catalyzed Ring-Opening of Epoxides
8.4K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
8.4K
02:24Acid-Catalyzed Ring-Opening of Epoxides
7.2K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.2K
01:19Nitrosation of Enols
2.6K
The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.
2.6K