The aza-Friedel–Crafts (aza-FC) reaction is a very powerful tool for forming C–C and C–N bonds, based on an acid-catalyzed addition of electron-rich aromatic compounds to imines. This reaction has been particularly useful for synthesizing polysubstituted amines bearing various aromatic groups, as this structural motif is present in many biologically active and pharmacologically relevant compounds. Through representative examples, recent improvements achieved on the aza-FC reaction are presented, classified according to the type of catalyst used. Particular emphasis has been put on the different catalysts used to obtain optically active compounds, as the stereoselective addition of a C(sp²)–H bond to an imine allows access to chiral amines in a completely atom-economical way.

Distinctive structural, chemical, and physical properties make the diarylmethane scaffold an essential constituent of many active biomolecules nowadays used in pharmaceutical, agrochemical, and material sciences. In this work, 33 novel diarylmethane molecules aiming to target colorectal cancer were designed. Two series of functionalized olefinic and aryloxy diarylmethanes were synthesized and chemically characterized. The synthetic strategy of olefinic diarylmethanes involved a McMurry cross-coupling reaction as key step and the synthesis of aryloxy diarylmethanes included an O-arylation step. A preliminarily screening in human colorectal cancer cells (HT-29 and HCT116) and murine primary fibroblasts (L929) allowed the selection, for more detailed analyses, of the three best candidates (10a, 10b and 12a) based on their high inhibition of cancer cell proliferation and non-toxic effects on murine fibroblasts (<100 µM). The anticancer potential of these diarylmethane compounds was then assessed using apoptotic (phospho-p38) and anti-apoptotic (phospho-ERK, phospho-Akt) cell survival signaling pathways, by analyzing the DNA fragmentation capacity, and through the caspase-3 and PARP cleavage pro-apoptotic markers. Compound 12a (2-(1-(4-methoxyphenyl)-2-(4-(trifluoromethyl)phenyl) vinyl) pyridine, Z isomer) was found to be the most active molecule. The binding mode to five biological targets (i.e., AKT, ERK-1 and ERK-2, PARP, and caspase-3) was explored using molecular modeling, and AKT was identified as the most interesting target. Finally, compounds 10a, 10b and 12a were predicted to have appropriate drug-likeness and good Absorption, Distribution, Metabolism and Excretion (ADME) profiles.

Aiming to create an innovative series of anti‐colorectal cancer agents, we designed in this work hybrid triarylmethane compounds. Three hybrid triarylmethanes and their corresponding N‐oxide analogues were successfully synthesized using an efficient procedure that involved connecting two triarylmethane molecules, through mono‐, bi‐, and triethylene glycol fragments. In our pursuit to develop more soluble molecules, we synthesized a hybrid triarylmethane featuring a lysine‐based spacer through a convergent strategy involving 7 steps. All hybrid compounds were assessed for their antiproliferative activity on human HT‐29 and HCT116 colorectal cancer (CRC) cell lines. Three pyridine N‐oxide analogs demonstrated notable antiproliferative potential among the set of tested compounds, with IC₅₀ values ranging from 18 to 24 μM on both human CRC cell lines analyzed. A cytotoxicity study conducted on murine fibroblasts revealed that these three active compounds were not toxic at the IC₅₀ values, indicating their suitability for further drug development. A docking study was conducted on two representative compounds, one for each series and protein kinase B (AKT) was identified as a potential target of their in anti‐cancer effects. A computational drug‐likeness study predicted favourable oral and intestinal absorption efficiency.

Triarylmethanes and triazoles constitute privileged structures extensively used in drug discovery programs. In this work, 12 novel triarylmethanes linked to a triazole ring were designed, synthesized, and chemically characterized aiming to target colorectal cancer. The synthetic strategy for triarylmethanes mono- and bi-substituted by a functionalized triazole ring involved a 1,3-dipolar cycloaddition. A preliminary screening in human colorectal cancer cells (HT-29 and HCT116) and murine primary fibroblasts (L929) allowed the selection of the best candidate 9b based on its high inhibition of cancer cell proliferation with an IC₅₀ of 11 μM on HT-29 and 14 μM on HCT116 and its non-cytotoxic effects on murine fibroblasts (<100 μM). A deep mechanistic study on various pathways showed that compound 9b induces caspase-3 cleavage, and its inhibitory effect on PARP activity is correlated with the increase of DNA fragmentation in cancer cells. Moreover, 9b induced apoptosis promoted by the inhibition of anti-apoptotic cell survival signaling pathways demonstrated via the downregulation of phosphorylated Akt and ERK proteins. Finally, the predicted binding modes of compounds 8c and 9b to five potential biological targets (i.e., AKT, ERK-1 and ERK-2, PARP and caspase-3) was evaluated using molecular modeling, and the predictions of the SuperPred webserver identified ERK2 as the most remarkable target. Also predicted in silico, 9b displayed appropriate drug-likeness and good absorption, distribution, metabolism and excretion (ADME) profiles.

Here we report a macrocyclization route towards the synthesis of glycophane peptides by a selective C−H arylation of the anomeric bond. This approach demonstrates the power of Pd‐catalysis C−H activation to access unusual cyclic peptides.