Sulfated Polyborate Catalyzed Improved Synthesis of Enamines and Enaminones Based Intermediates of Imatinib, Nilotinib and Ocinaplon**

Abstract

AbstractAn activation of methyl ketones or active methylenes and N, N‐dimethylformamide dimethyl acetal at 110 °C by sulfated polyborate under solvent‐free conditions has been developed for enamines and enaminones synthesis. Selected Brønsted acid, optimized reaction conditions, and easy separation method lead to 82–97 % yield, making this process cost‐effective and eco‐friendly. We chose boric acid for scale‐up activity in the interest of readers and industries. The optimized reaction condition was applied to demonstrate a 10 gram scale for the intermediate of Imatinib and Nilotinib with an 80 % from 3‐acetylpyridine. This method is extendable to produce Ocinaplon intermediate with 80.6 % yield using 4‐acetyl pyridine as starting material.