The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Electronic effects in tautomeric equilibria: The case of chiral imines from D-glucamine and 2-hydroxyacetophenones

Electronic effects in tautomeric equilibria: The case of chiral imines from D-glucamine and 2-hydroxyacetophenones
Electronic effects in tautomeric equilibria: The case of chiral imines from D-glucamine and 2-hydroxyacetophenones
A one-pot procedure for preparing a series of chiral imines by direct condensation of D-glucamine with 2-hydroxyacetophenones is described. Under conventional acetylation an unexpected mixture of two different peracetylated molecules is obtained, one with an open enamine structure, and the other incorporating an N-acetyl-1,3-oxazolidine into the acyclic skeleton. Surprisingly, both molecules coexist within the crystal's unit cell, as inferred from single-crystal X-ray analysis of a 5-bromo-substituted aryl derivative. Moreover, the 1,3-oxazolidine ring exists as rotational conformers (E,Z) owing to the restricted rotation around the N-acetyl bond. The equilibrium involving imine and enamine structures has been assessed in detail, providing in addition linear free-energy relationships between the tautomerization constants (KT) and the electronic effect of the substituents.
1477-0520
10209-10222
Matamoros, Esther
67ecaf15-3e62-46d8-b8fd-717f8e8c439a
Cintas, Pedro
29979233-8382-47a8-bde7-1faf4869308c
Light, Mark
cf57314e-6856-491b-a8d2-2dffc452e161
Palacios, Juan C.
2c06e379-89b3-46b1-95c8-7f5057732f9f
Matamoros, Esther
67ecaf15-3e62-46d8-b8fd-717f8e8c439a
Cintas, Pedro
29979233-8382-47a8-bde7-1faf4869308c
Light, Mark
cf57314e-6856-491b-a8d2-2dffc452e161
Palacios, Juan C.
2c06e379-89b3-46b1-95c8-7f5057732f9f

Matamoros, Esther, Cintas, Pedro, Light, Mark and Palacios, Juan C. (2019) Electronic effects in tautomeric equilibria: The case of chiral imines from D-glucamine and 2-hydroxyacetophenones. Organic & Biomolecular Chemistry, 17 (48), 10209-10222. (doi:10.1039/C9OB02147G).

Record type: Article

Abstract

A one-pot procedure for preparing a series of chiral imines by direct condensation of D-glucamine with 2-hydroxyacetophenones is described. Under conventional acetylation an unexpected mixture of two different peracetylated molecules is obtained, one with an open enamine structure, and the other incorporating an N-acetyl-1,3-oxazolidine into the acyclic skeleton. Surprisingly, both molecules coexist within the crystal's unit cell, as inferred from single-crystal X-ray analysis of a 5-bromo-substituted aryl derivative. Moreover, the 1,3-oxazolidine ring exists as rotational conformers (E,Z) owing to the restricted rotation around the N-acetyl bond. The equilibrium involving imine and enamine structures has been assessed in detail, providing in addition linear free-energy relationships between the tautomerization constants (KT) and the electronic effect of the substituents.

Text
Accepted-Ms-OB-ART-10-2019-002147 - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 15 November 2019
e-pub ahead of print date: 19 November 2019
Published date: 28 December 2019

Identifiers

Local EPrints ID: 436412
URI: http://eprints.soton.ac.uk/id/eprint/436412
ISSN: 1477-0520
PURE UUID: 238213d2-1f78-4016-97ca-388a578a4ae3
ORCID for Mark Light: ORCID iD orcid.org/0000-0002-0585-0843

Catalogue record

Date deposited: 10 Dec 2019 17:30
Last modified: 22 Nov 2021 07:53

Export record

Altmetrics

Contributors

Author: Esther Matamoros
Author: Pedro Cintas
Author: Mark Light ORCID iD
Author: Juan C. Palacios

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×