Adipic/glutamic and oxalic/glutamic-based deep eutectic solvents as potent catalysts for the green synthesis of tetrazoloquinazolinones

Two bio-based deep eutectic solvents (DESs), namely Adp/Glu-DES based on adipic acid (Adp) and glutamic acid (Glu) in a 1:1 molar ratio and Oxa/Glu-DES , composed of oxalic acid (Oxa) and Glu in a molar ratio of 3:1, were successfully prepared. The formation of both DESs was confirmed by FT-IR spectroscopy, 1 H NMR, UV-Vis spectroscopy, thermal analysis, viscosity measurements, and determination of the eutectic point, demonstrating the formation of homogeneous and transparent eutectic systems. These DESs were subsequently employed as efficient and recyclable catalysts for the one-pot three-component condensation reaction of 5-aminotetrazole, dimedone, and aromatic aldehydes for the synthesis of tetrazoloquinazolinones. A wide range of substrates smoothly afforded the corresponding products under mild and environmentally benign conditions, providing good to excellent yields. Furthermore, both Oxa/Glu-DES and Adp/Glu-DES can be easily recovered and reused in multiple catalytic cycles without a significant reduction in catalytic activity, highlighting their potential as a stable and metal-free catalytic environment for the synthesis of heterocyclic compounds with medicinal value.