Synthesis of 5, 6-diaroylisoindoline-1, 3-dione and computational approaches for investigation on structural and mechanistic insights by DFT

ABSTRACT

This study represents a theoretical investigation of the coupling reaction between isoindoline-1, 3-dione (phthalimide) and aroyl chloride. Firstly, density functional theory (DFT) was employed to explore the structural insights of the coupled product 5, 6-diaroyl isoiondoline-1, 3-dione. The dispersion corrected functional ωB97X-D was applied to determine the transition states of the coupling reaction in the gas phase and in the solution phase by the SMD solvation model. In two-step mechanism, the calculated results indicate that the energy barrier of the C–C bond formation between benzoyl cation and phthalimide is the rate determining step of the reaction, and the activation energy was found 53.3 kcal/mol in1,4-dioxane. Moreover, thermodynamic calculation shows that the aroylation reactions are either spontaneous or nonspontaneous depending on the aroyl halide used although all these reactions are exothermic. However, B3LYP/6-311+G (d, p) functional was applied to compute equilibrium geometry, HOMO–LUMO energy gap (3.9–4.1 eV), dipole moments, polarizability and first order hyper polarizability to understand the structural features of the products. Moreover, experimental and computed FT-IR analysis of the phthalimide derivatives showed well correlation. Finally, for the synthesis of 5, 6-diaroyl isoiondoline-1, 3-dione from phthalimide and aroyl halide is herein described.

KEYWORDS:

• Isoindoline-1, 3-dione
• aroylation
• density functional theory (DFT)
• transition states

Acknowledgements

The authors gratefully acknowledge for the financial support of Bangladesh University of Engineering and Technology, Dhaka. The authors also thankful to Dr. Mohammad A. Halim, Division of Computer-Aided Drug Design, The Red-Green Research Centre, BICCB, Dhaka, Bangladesh and Department of Physical Sciences, University of Arkansas Fort Smith, Fort Smith, Arkansas, USA for the support of his computational resources

Author contributions

Hoque MM and Hossain MS developed the synthetic protocol and synthesised the relevant compounds. Hoque MM organised the idea and performed quantum mechanical calculations, executed data collection and wrote the manuscript. Khan MW supervised this work and revised the manuscript. Kumer A also revised the manuscript. All authors read and permitted the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).