Pyridazinic Bioisosteres with Potential Applications in Medicinal Chemistry and Agriculture

Abstract

Bioisosteres are substituents or groups (atoms, ions, or molecules) with similar chemical or physical properties, and which usually have similar biological properties. Pyridazine and its derivatives are invaluable scaffolds in medicinal chemistry, having a large variety of activities such as antibacterial, antifungal, antimalarial, anticancer, antituberculosis, antihypertensive, etc. Also, the pyridazine core is of high interest in agriculture, being used as a growth factor for plants, herbicides, etc. This study aims to review our previous contributions related to antimicrobials and the germination and seedling capabilities of some seeds and plants of some pyridazine classical and nonclassical bioisosteres. So, we present herein the synthesis (under conventional thermal heating and microwave irradiation) and spectral characterization of seven series of pyridazine bioisosteres, the in vitro antimicrobial activity (against different strains of Gram-positive and Gram-negative bacteria and fungi), and the biologic effect on wheat germination and seedling growth. Some pyridazine bioisosteres proved to have very good activity against pathogenic bacterial strains, with some spectacular results. Overall, nonclassical bioisosteres prove to have better antibacterial and antifungal activity compared with classical bioisosteres. The pyridazine bioisosteres may influence the wheat germination rate, seedling growth, height, and weight of the plantlets. Feasible explanations for this behaviour were furnished.