ZnCl2-mediated practical protocol for the synthesis of Amadori ketoses

•An efficient and practical protocol for few Amadori ketoses accomplished.•The catalytic protocol circumvents separation techniques.•Amadori ketoses exhibit moderate to weak ACE inhibitory activity. An efficient and practical protocol for the synthesis of Amadori ketoses N-(1-deoxy-d-fructose-1-yl) amino acid (amino acid=l-valine (1), l-leucine (2), l-isoleucine (3), l-tryptophan (4), l-phenylalanine (5), l-arginine (6) has been accomplished by employing ZnCl2 as a catalyst. The developed method circumvents protection and deprotection steps as well as tedious ion-exchange and column chromatographic techniques. The accomplished Amadori ketoses showed moderate to weak angiotensin I converting enzyme (ACE) inhibitory activity.