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Electronic effects in tautomeric equilibria: The case of chiral imines from D-glucamine and 2-hydroxyacetophenones
- Publication Year :
- 2019
-
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.
- Subjects :
- 010405 organic chemistry
Aryl
Organic Chemistry
Imine
010402 general chemistry
01 natural sciences
Biochemistry
Tautomer
0104 chemical sciences
Enamine
chemistry.chemical_compound
chemistry
Computational chemistry
Electronic effect
Molecule
Physical and Theoretical Chemistry
Conformational isomerism
Derivative (chemistry)
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....4d1b93503e10167de53127b632e75648