Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement

Ligand-based design and synthesis of new trityl histamine and trityl cysteamine derivatives as SIRT2 inhibitors for cancer therapy

The relentless pursuit of novel therapeutic agents against cancer has led to the identification of multiple molecular targets, among which Sirtuin 2 (SIRT2) has garnered significant attention. This study presents an extensive SAR study of our reported trityl scaffold-based SIRT2 inhibitors. This study encompasses a range of different medicinal chemistry approaches to improve the activity of the lead compounds TH-3 and STCY1. The rationally designed and synthesized structures were confirmed using NMR and high-resolution mass spectroscopy before performing SIRT2 inhibition assay, NCI60 cytotoxicity test, and cell cycle analysis. Indeed, our strategies afforded hitherto unreported SIRT2 inhibitors with high activity, particularly 2a, 4a, 7c, and 7f. Remarkably, the presence of a lipophilic para substitution on the phenyl group of a freely rotating or a locked trityl moiety enhanced activity SIRT2 inhibition. Concomitantly, the synthesized compounds showed prominent activity against different cancer lines from the NCI60 assay. Of interest, compound 7c stands out as a potent and highly selective antiproliferative agent against leukemia and colon cancer panels. Furthermore, 7c treatment resulted in cell cycle arrest in MCF-7 cells at G2 phase and did not cause in vitro DNA cleavage.

Exploring the Acid-Catalyzed Reactions of 10,11-Epoxy-Dibenzo[a,d]cycloheptan-5-ol as the Synthetic Modules toward Polycyclic Aromatic Scaffolds

The structural diversity of polycyclic aromatic hydrocarbons (PAHs) offers exciting opportunities for their applications. Yet, selective synthesis of such conjugated networks poses a formidable challenge. Compared to the prominence of transition-metal-catalyzed cross-coupling and oxidative Scholl reactions, cationic rearrangement in the synthesis of polycyclic aromatic hydrocarbon is an underexplored subject. In this study, we reveal that cationic intermediate generated from epoxy dibenzocycloheptanol can be transformed into acenes, azulene-embedded PAHs, and dibenzocycloheptanone derivatives. Reactive patterns, including Meinwald rearrangement, Nazarov cyclization, transannular aryl migration, and transannular Friedel-Crafts cyclization were identified. Both substrate structures and reaction temperature affect the reaction pathways in predictable and manageable manners. A mechanistic scheme was postulated as the working model to guide the reactivity for further application. Substrates containing heterocyclic and ferrocenyl groups exhibit similar reactivity profiles. The inquiry culminates in the selective synthesis of 5, 7, 12, 14-tetrasubstituted C _2h and C _2v pentacene derivatives. Our results demonstrate that polycyclic aromatic hydrocarbons can be selectively prepared with this cation-initiated strategy by methodically tuning the reactivity.

4b-Aryltetrahydroindeno[1,2-a]indenes by Acid-Catalyzed Trans­annular Cyclization of Benzannulated Cyclooctene Alcohols

By starting from two simple building blocks, benzannulated cyclooctenones were obtained in three steps. Subsequent Grignard/aryl lithium addition to the ketone yielded the corresponding tertiary alcohols that underwent stereoselective acid-catalyzed transannular cyclization to provide a cis-fused 5/5 bicyclic indanylindane framework exclusively. Subsequent stereoselective nucleophilic addition to the indanyl cation by hydride, water, or electron-rich aromatics furnished the 4b-aryltetrahydroindano[1,2-a]indenes in good to excellent yields (up to 92%) in the trans-C9–C9a form in up to a >99:1 diastereomeric ratio.