-catalyzed formal [3 + 2] cycloaddition for diverse naphtho[1,2-]furan-3-carboxamides and their biological evaluation

Diverse naphtho(1,2-b)furan-3-carboxamide derivatives 12a-12q were synthesized in high yield via the novel Re2O7-catalyzed formal (3+2) cycloaddition of 1,4- naphthoquinones with β-ketoamides as the key step. This methodology offers several advantages, such as environ- mentally benign character, the use of a mild catalyst, high yields, and ease of handling. The synthesized compounds werescreenedfortheirtyrosinaseinhibitory,antioxidant,and antibacterial activities. The results showed that compound