Tautomerism in Pindone – A DFT Study

Lemi Türker

doi:10.34198/ejcs.3120.3550

Abstract

Pindone is a rodenticide having three keto groups in its structure. Presently, 1,3-type keto-enol tautomerism of pindone has been studied within the constraints of density functional theory at the level of B3LYP/6-311++G(d,p). Various structural and quantum chemical properties of these tautomers have been obtained, compared and discussed. Endocyclic and exocyclic enol forms of pindone are accompanied by dipole moment vectors having opposite directions. The endocyclic enol structure is found to be more stable than the exocyclic enol and pindone. IR and UV-VIS spectra are obtained. NICS(0) values are calculated to visualize the effect of tautomerism on the local aromaticity of the structures considered.

Highlights

Pindone (2-Pivalyl-1,3-indandione) is a first generation anticoagulant rodenticide of the indandione type, as are chlorophacinone and diphacinone [1]
The efficacy of first generation products such as warfarin has been reduced by the development of resistance in some parts of the world, and they have largely been superseded by second generation anticoagulants of the hydroxycoumarin type, such as bromadiolone and brodifacoum
The total electronic energies have been corrected for the zero point vibrational energy (ZPE)

Summary

Introduction

Pindone (2-Pivalyl-1,3-indandione) is a first generation anticoagulant rodenticide of the indandione type, as are chlorophacinone and diphacinone [1]. The efficacy of first generation products such as warfarin (a first generation hydroxycoumarin) has been reduced by the development of resistance in some parts of the world, and they have largely been superseded by second generation anticoagulants of the hydroxycoumarin type, such as bromadiolone and brodifacoum. These newer compounds are lethal to target rodents after a single feed, death is delayed for some days. One of them is pindone which is prepared by condensation of diethyl phthalate and pinacolone

Methods

Results

Conclusion