Green synthesis of novel spiropyrazoline-indolinones in neutral deep eutectic solvents and DFT studies

Zubi Sadiq; Ambreen Ghani; Muhammad A Hashmi; A Dahshan; Shahnaz; Samiah H Al-Mijalli; Munawar Iqbal; Erum A Hussain

doi:10.1016/j.heliyon.2023.e23814

Green synthesis of novel spiropyrazoline-indolinones in neutral deep eutectic solvents and DFT studies

Heliyon. 2023 Dec 20;10(1):e23814. doi: 10.1016/j.heliyon.2023.e23814. eCollection 2024 Jan 15.

Authors

Zubi Sadiq¹, Ambreen Ghani², Muhammad A Hashmi³, A Dahshan⁴, Shahnaz¹, Samiah H Al-Mijalli⁵, Munawar Iqbal⁶, Erum A Hussain¹

Affiliations

¹ Department of Chemistry, Lahore College for Women University, Lahore, 54000, Pakistan.
² Department of Chemistry, University of Education Lahore, Vehari Campus, 61100, Pakistan.
³ Department of Chemistry, University of Education, Attock Campus, Attock, 43600, Pakistan.
⁴ Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia.
⁵ Department of Biology, College of Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia.
⁶ Department of Chemistry, Division of Science and Technology, University of Education, Lahore, Pakistan.

Abstract

Novel spiropyrazoline-indolinones (4a-t) have been synthesized successfully in neutral deep eutectic solvents by reacting 5-Cl/Br-isatin (1a-b) with aromatic ketones (2a-b) and a variety of substituted hydrazines (3a-e) in good to excellent yields. This eco-friendly straightforward synthetic protocol discloses good functional group compatibility. The conventional synthetic approach was compared with the greener route of microwave-assisted synthesis of spiropyrazolines using ethanol. This approach utilized mild reaction conditions which furnished high yields in short reaction time employing one pot two-step multicomponent. All new compounds were structurally confirmed by detailed spectroscopic analysis and density functional theory calculations. This method provides efficient access to spiropyrazole derivatives using biodegradable and green solvent.

Keywords: Deep eutectic solvent; Density functional theory; Intramolecular cyclization; Spiropyrazoline.