Natural deep eutectic solvents [BetaineCl][Lactic acid] as efficient and sustainable catalyst for one-pot synthesis of α-aminophosphonates

Organophosphorus compounds have fascinated significant interest for their broad biological relevance and diverse uses. However, alpha-aminophosphonates are important compounds and remain challenging; their preparation is highlighting the need for innovative and eco-friendly methods. Herein, we have interested on the preparation of alpha-aminophosphonate derivatives through Kabachnik-Fields reaction using the synthesized Natural Deep Eutectic Solvents (NaDES) as novel catalyst, which are more environmentally benign than conventional solvents. Seven NaDES were developed using Betaine as the Hydrogen Bond Acceptors (HBA) and natural carboxylic acids as Hydrogen Bond Donors (HBD), and then tested across various molar ratios. Among them, the Betaine:Lactic Acid combination with a (1:2) molar ratio proved to be the most effective. It exhibited excellent catalytic performance over four cycles on a multi-gram scale, consistently achieving high yields of the desired products.