Sodium Copper Chlorophyllin: A Sustainable Bioinspired Catalyst for the Aerobic Oxidative Synthesis of Nitrogen Heterocycles and the Oxidative Cyanation of Tertiary Amines

Abstract

AbstractA remarkably simple and straightforward protocol has been reported showcasing sodium copper chlorophyllin (SCC) as an eco‐friendly, bioinspired catalyst for the aerobic oxidative synthesis of pharmaceutically prevalent nitrogen‐containing heterocycles, such as benzimidazoles and quinoxalines. This reaction was performed in green solvent water, using the green oxidant, molecular oxygen. SCC displayed exceptional efficiency, congruent with the prevailing metal/non‐metal‐based catalyst regime without requiring additives. The SCC catalyst exhibited excellent recyclability upto three cycles for the benzimidazole synthesis reaction. This benign strategy was successfully applied in synthesizing a bioactive quinoxaline i. e., Tyrphostin AG1296, a promising candidate for melanoma treatment. The catalytic activity of SCC was explored for the synthesis of another privileged moiety i. e., α‐aminonitriles, via the α‐cyanation of tertiary amines under oxidative conditions. This reaction progressed with a mild, easy‐to‐use, convenient cyanide source, such as ethyl cyanoformate, and a green and attractive solvent, such as methanol, precluding acidic media. SCC catalyst was efficiently recycled upto three cycles for the α‐aminonitriles synthesis. Overall, the utility of a biodegradable, robust catalyst such as SCC, eco‐friendly solvents such as water and methanol, green oxidants such as O2, and mild reaction conditions, devoid of acidic additives, renders the present work viable for academic and industrial research.