Related Experiment Video
Updated: Jul 17, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Structures of the intermediates formed in the ring-opening reaction of 2-chloro-3-nitropyridine
LeRoy W Haynes1, Virginia B Pett
1Department of Chemistry, The College of Wooster, Wooster, Ohio 44691, USA. haynes@wooster.edu
Abstract:
The reaction of 2-chloro-3-nitropyridine with two equivalents of hydroxide ion was studied by NMR and X-ray crystallography. On the basis of NMR coupling constants, the originally formed ring-opened intermediate is the pseudo-cis form, as predicted by the SN(ANRORC) mechanism. However, the first intermediate is unstable and isomerizes to a second intermediate, which was isolated. The pseudo-trans geometry of the second intermediate [3-pentenenitrile, 2-nitro-5-oxo, ion(-1), sodium] explains why additional base does not lead to the ring-closing reaction as observed with 2-chloro-5-nitropyridine.
Related Concept Videos
Base-Catalyzed Ring-Opening of Epoxides
Acid-Catalyzed Ring-Opening of Epoxides
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Preparation of Nitriles
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...

