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This protocol describes a procedure for the Ugi four-component condensation. It describes the general mechanism as well as the effects of the nature of the components on the Ugi reaction. It also describes the effects of the reaction conditions on the reaction, along with special procedures and workup. The experimental procedure is exemplified by a description of the preparation of N-cyclohexyl 2-[N-(2-chloroacetyl)-N-(4-chlorobenzyl)]amino-2-(4-chlorophenyl)acetamide, a typical Ugi product, that is subsequently used for the synthesis of a 2,5-diketopiperazine, an example of an important type of pharmaceutical compound. The experimental procedure is then extended to the synthesis of a 1,5-disubstituted tetrazole via Ugi four-component condensation. The protocol describes the preparation and characterization of the new 1-cyclohexyl-5-(1-phenylamino-2-methyl)propyltetrazole. The total time for the synthesis and isolation of the two example reactions in parallel is 3 d.

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Plastic degradation by biological systems with re-utilization of the by-products could be a future solution to the global threat of plastic waste accumulation. Here, we report that the saliva of Galleria mellonella larvae (wax worms) is capable of oxidizing and depolymerizing polyethylene (PE), one of the most produced and sturdy polyolefin-derived plastics. This effect is achieved after a few hours’ exposure at room temperature under physiological conditions (neutral pH). The wax worm saliva can overcome the bottleneck step in PE biodegradation, namely the initial oxidation step. Within the saliva, we identify two enzymes, belonging to the phenol oxidase family, that can reproduce the same effect. To the best of our knowledge, these enzymes are the first animal enzymes with this capability, opening the way to potential solutions for plastic waste management through bio-recycling/up-cycling.

The transmembrane anion transport activity of a series of synthetic molecules inspired by the structure of tambjamine alkaloids can be tuned by varying the lipophilicity of the receptor, with carriers within a certain log P range performing best.

A quinoline-indene derivative is described as a new highly selective and sensitive chromogenic and turn-on fluorogenic probe for the naked-eye detection of copper(II) cation in water-acetonitrile 1:1 mixture.

Synthetic prodiginine obatoclax shows promise as a potential anticancer drug. This compound promotes apoptosis of cancer cells, although the mechanism of action is unclear. To date, only the inhibition of BCL-2 proteins has been proposed as a mechanism of action. To gain insight into other possible modes of action, we have studied the anion-binding properties of obatoclax and related analogues in solution, in the solid state, and by means of density functional theory calculations. These compounds are well suited to interact with anions such as chloride and bicarbonate. The anion-transport properties of the compounds synthesized were assayed in model phospholipid liposomes by using a chloride-selective-electrode technique and (13)C NMR spectroscopy. The results demonstrated that these compounds are efficient anion exchangers that promote chloride, bicarbonate, and nitrate transport through lipid bilayers at very low concentrations. In vitro studies on small-cell lung carcinoma cell line GLC4 showed that active ionophores are able to discharge pH gradients in living cells and the cytotoxicity of these compounds correlates well with ionophoric activity.

5-Oxobenzo[e][1,4]diazepine-3-carboxamides were synthesized by sequential Ugi reaction-Staudinger/aza-Wittig cyclization. The pseudopeptidic backbone of the new benzodiazepine derivatives superimposed well with type I, I', II, and II' beta-turn motifs. The intermediate Ugi adducts were characterized as two conformers of the enol form by the correlation between (1)H NMR spectra and X-ray diffraction structures of model compounds.