Previously, we synthesized and evaluated several benzofuran derivatives containing heterocyclic ring substituents linked to the benzofuran nucleus at C-2 by a two- to four-atom spacer as potential anti-HIV-1, anticancer and antimicrobial agents. Among these derivatives, NSC 725612 and NSC 725716 exhibited interesting anti-HIV-1 activity. To further investigate the structure-activity relationship, we synthesized several new benzofuran derivatives derived from 2-acetylbenzofuran (2, 3a-c) and 2-bromoacetylbenzofuran (6; 7a,b; 8a,b). The compounds were designed to comprise the heterocyclic substituents directly linked to the benzofuran nucleus at C-2. Moreover, various related benzimidazoles derived from 2-acetylbenzimidazole and from 2-cyanomethylbenzimidazole (12a,b; 13a,b; 15; 16a,b) were also prepared as isosteres. The synthesized compounds were preliminarily evaluated for their in vitro anti-HIV-1, anticancer and antimicrobial activity. Compounds 2, 3a, 3b, and 12b showed weak anti-HIV-1 activity. Compound 6 exhibited mild activity against S. aureus, while compound 15 had mild activity towards S. aureus and C. albicans. However, no significant anticancer activity was observed with any of the tested compounds. From these results, we conclude that the presence of the spacer between the heterocyclic substituent and the benzofuran nucleus may be essential for the biological activity.

The natural cembranolide sarcophine (3) and its lactone ring-opened analogue (10) were oxidized using selenium dioxide under different reaction temperatures to prepare hydroxylated derivatives. Nine new compounds were obtained, six of them targeted hydroxylated derivatives. The determination of regio- and stereochemistry as well as the mechanistic considerations on the selectivity observed in these reactions are discussed on the basis of 2D NMR and molecular modeling. In preliminary in vitro tests on inhibition of EBV-EA activation, compounds 10 and 12-15 have shown higher activity than the known chemopreventive agent sarcophytol A.