A Focused Library of NO-Donor Compounds with Potent Antiproliferative Activity Based on Green Multicomponent Reactions

Cancer is the second leading cause of death worldwide. Herein, a strategy to quickly and efficiently identify novel lead compounds to develop anticancer agents, using green multicomponent reactions followed by antiproliferative activity and structure–activity relationship studies, is described. A second-generation focused library of nitric oxide-releasing compounds was prepared by microwave-assisted Passerini and Ugi reactions. Nearly all compounds displayed potent antiproliferative activities against a panel of human solid tumor cell lines, with 1-phenyl-1-[(tert-butylamino)carbonyl]methyl 3-[(3-phenylsulfonyl-[1,2,5]oxadiazol-4-yl N-oxide)oxy]benzoate (4 k) and N-[1-(tert-butylaminocarbonyl)-1-phenylmethyl]-N-(4-methylphenyl)-3-(3-phenylsulfonyl-[1,2,5]oxadiazol-4-yl N-oxide)oxyphenyl carboxamide (6 d) exhibiting the strongest activity on SW1573 lung cell line (GI=110 and 21 nm) with selectivity indices of 70 and 470, respectively. Preliminary mechanistic studies suggest a relationship between NO release and antiproliferative activity. Our strategy allowed the rapid identification of at least two molecules as future candidates for the development of potent antitumor drugs.