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Seventeen novel 2-(5-amino-1-(substituted sulfonyl)-1H-1,2,4-triazol-3-ylthio)-6- isopropyl-4,4-dimethyl-3,4-dihydronaphthalen-1(2H)-one compounds were synthesized from the abundant and naturally renewable longifolene and their structures were confirmed by FT-IR, NMR, and ESI-MS. The in vitro cytotoxicity of the synthesized compounds was evaluated by standard MTT assay against five human cancer cell lines, i.e., T-24, MCF-7, HepG2, A549, and HT-29. As a result, compounds 6d, 6g, and 6h exhibited better and more broad-spectrum anticancer activity against almost all the tested cancer cell lines than that of the positive control, 5-FU. Some intriguing structure–activity relationships were found and are discussed herein by theoretical calculation.

A visible light-induced cascade cyclization of thioamides with alkynes was developed to synthesize 1,3-thiozoles. The sulfur radical generated from thioamide via the single-electron transfer (SET) pathway was promoted by photocatalysis as a key intermediate in this reaction. When bromoalkynes were used as the substrate, the self-coupling products 1,1-dibromo-1-en-3-ynes were obtained in moderate yields, and an energy transfer pathway for this transformation promoted by visible-light photocatalysis was proposed.

In order to develop novel chemotherapeutic agents with potent anticancer activities, a series of dehydroabietic acid (DHA) derivatives bearing an acylhydrazone moiety were designed and synthesized by the condensation between dehydroabietic acylhydrazide (3) and a variety of substituted arylaldehydes. The inhibitory activities of these compounds against CNE-2 (nasopharynx), HepG2 (liver), HeLa (epithelial cervical), and BEL-7402 (liver) human carcinoma cell lines were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay in vitro. The screening results revealed that many of the compounds showed moderate to high levels of anticancer activities against the tested cancer cell lines and some displayed similar potent inhibitory activities to the commercial anticancer drug cisplatin, while they exhibited lower cytotoxicity against normal human liver cell (HL-7702). Particularly, compound 4w, N’-(3,5-difluorobenzylidene)-2-(dehydroabietyloxy)acetohydrazide, with an IC50 (50% inhibitory concentration) value of 2.21 μM against HeLa cell, was about 17-fold more active than that of the parent compound, and showed remarkable cytotoxicity with an IC50 value of 14.46 μM against BEL-7402 cell. These results provide an encouraging framework that could lead to the development of potent novel anticancer agents.