Oligo Tröger's bases are compounds containing two or more Tröger's base subunits (1,5-methanodiareno[b,f][1,5]diazocines) sharing one or more arene parts. Due to their interesting molecular shapes, these compounds are studied as chiral molecular tweezers, clips, cavitands, clefts, calixes, etc. This review includes all available data on oligo Tröger's bases, and introduces their preparation and properties to a wide audience.

A novel methodology for preparation of linear oligopyrroles is presented. Synthetic protocol uses water as a solvent for acid catalysed condensation of an aldehyde or ketone with unsubstituted pyrrole. While the most procedures for the above-mentioned compounds are performed in organic solvents, or large excess of pyrrole (used as solvent), we present here a novel, mild and efficient procedure for selective preparation of linear oligopyrroles in aqueous environment. Preparation of dipyrromethanes 3 and tripyrromethanes 4 was optimised by varying the molar ratio and concentrations of starting compounds (aldehyde to pyrrole) and acid catalyst. The high initial concentration of aldehyde and pyrrole leads to the preferential formation of 3, where the driving force for the product formation is precipitation of 3 from water solution; the reaction proceeds at room temperature within a couple of minutes in excellent yields. On the other hand, low concentration of starting compounds led to preferential formation of tripyrromethanes 4. Formation of 3 and 4 can also be controlled by the initial ratio of aldehyde and pyrrole, where generally the ratios over 1:6 gave mostly 3. Application of this synthetic protocol for ketones revealed that only 3 are formed, regardless of the ratio of starting compounds, which is interpreted as a result of lower reactivity of ketones in this particular condensation reaction.

Cardiac glycosides (CGs) represent a group of sundry compounds of natural origin. Most CGs are potent inhibitors of Na⁺/K⁺-ATPase, and some are routinely utilized in the treatment of various cardiac conditions. Biological activities of other lesser known CGs have not been fully explored yet. Interestingly, the anticancer potential of some CGs was revealed and thereby, some of these compounds are now being evaluated for drug repositioning. However, high systemic toxicity and low cancer cell selectivity of the clinically used CGs have severely limited their utilization in cancer treatment so far. Therefore, in this study, we have focused on two poorly described CGs: hyrcanoside and deglucohyrcanoside. We elaborated on their isolation, structural identification, and cytotoxicity evaluation in a panel of cancerous and noncancerous cell lines, and on their potential to induce cell cycle arrest in the G2/M phase. The activity of hyrcanoside and deglucohyrcanoside was compared to three other CGs: ouabain, digitoxin, and cymarin. Furthermore, by in silico modeling, interaction of these CGs with Na⁺/K⁺-ATPase was also studied. Hopefully, these compounds could serve not only as a research tool for Na⁺/K⁺-ATPase inhibition, but also as novel cancer therapeutics.

4,6-Bis(bromomethyl)-N¹,N³-bis(tert-butoxycarbonyl)benzene-1,3-diamine is introduced as a general starting compound for the preparation of bis-Tröger's base (bisTB) derivatives in excellent yield in just two steps. The synthetic sequence includes treatment of the above-mentioned protected diamine with an arylamine followed by in situ deprotection and the final bisTB-forming reaction. This sequence allows synthesis of bisTB derivatives, which are not accessible by known procedures. The described approach is a general new method for the preparation of bisTB derivatives from "troegerable" arylamines.