An Alternative Green Method for Synthesis of 3-Amino-5-Methylisoxazole Schiff Bases and Their Bioactivity Evaluation

Isoxazole Schiff bases play an important role in medicinal chemistry, pharmacy, coordination chemistry, and industrial chemistry, therefore, finding easier and more reliable procedures for their synthesis is still in process. The present work deals with a single-step condensation reaction between 3-amino-5-methylisoxazole and various aromatic aldehydes to furnish a Schiff base scaffold of isoxazole (including one new compound) with excellent yields in a short time. The procedure is a solvent-free condition using DMEA as a green catalyst. The products were evaluated for their antibacterial efficacy against gram-positive and gram-negative bacteria including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Salmonella abony. The antioxidant activity of the products was tested and the ascorbic acid and quercetin were used as standards. The produced Schiff bases exhibited the ability to scavenge the free radicals from the DPPH. This means that the products can be used as antioxidants. Two of the synthesized compounds were evaluated for their anticancer activity by testing their cytotoxic potency, which showed diminishing toxicity of cell lines against human breast cancer cell lines and gastric adenocarcinoma cell lines. Therefore, the products can be utilized as anticancer agents.