Hannah

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Introduction

Tautomers of Acetylacetone (C5H8O2)

-Keto = ketone
-Enol = alcohol
-may also be referred to as an alkenol
-Usually the keto tautomer is favored
-The basic reaction: basic

Why Tautomerization Matters

-Different solvents may change the equilibrium of the keto- and enol- forms
-Tautomers in DNA replication have been hypothesized to contribute to mutagenic mispairings
-"whereas in RNA, minor tautomeric forms have been proposed to enhance the structural and functional diversity of RNA enzymes and aptamers" (https://rnajournal.cshlp.org/content/21/1/1.full.html)


F1.large.jpg

WebMO

-All calculations were done using HF/6-31G(d)

Keto Acetylacetone

Molecule (2).png

Proton NMR NmrKetoZoomed.png

Proton NMR shifts:File:NMR-Chemical-Shift-PPM-Range-and-Values-Table-.png

Enol Acetylacetone

Molecule.png

Proton NMR NmrEnol2.png

Proton NMR shifts:File:NMR-Chemical-Shift-PPM-Range-and-Values-Table-.png

N.B. Hydrogen bonding deshields the proton, further increasing the chemical shift