Tomás Torroba

The use of the Ugi four-component condensation

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.

A New Selective Chromogenic and Turn-On Fluorogenic Probe for Copper(II) in Water−Acetonitrile 1:1 Solution

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 (GX15‐070) and Related Analogues: Anion Binding, Transmembrane Transport, and Cytotoxicity Properties

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.

Fluorescent Discrimination between Traces of Chemical Warfare Agents and Their Mimics

An array of fluorogenic probes is able to discriminate between nerve agents, sarin, soman, tabun, VX and their mimics, in water or organic solvent, by qualitative fluorescence patterns and quantitative multivariate analysis, thus making the system suitable for the in-the-field detection of traces of chemical warfare agents as well as to differentiate between the real nerve agents and other related compounds.

The role of lipophilicity in transmembrane anion transport

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.

Synthesis of indole derivatives via isocyanides

Fast and convenient approaches to the indole nucleus from isocyanides are reviewed as a means for the tailored preparation of conveniently functionalized indoles by using the unique reactivity of isocyanides in one-pot multicomponent and cascade reactions.

Sulfur-Nitrogen Heterocycles

For more than a century, heterocycles have constituted one the largest areas of research in organic chemistry.[...]

Synthesis of thiomorpholines by an intramolecular Ugi reaction

The Ugi four-component condensation between 5-oxo-3-thiacarboxylic acids, benzylamines and cyclohexyl isocyanide gave 5-oxothiomorpholine-3-carboxamides. The configuration of bicyclic thiomorpholine derivatives was established by NOESY experiments.

Cyclopentathiadiazines, new heterocyclic materials from cyclic enaminonitriles

Indene and cyclopentene enaminonitriles were reacted with SCl2, iBu3N and NCS to give the first cyclopenta[1,2,6]thiadiazines that showed unusual characteristics, one as a NIR dye and another as a liquid crystal.

Synthesis of poly-ferrocene heterocycles by cycloaddition of mono- or bis(ferrocenecarbonyl)acetylenes and bis[1,2]dithiolo[1,4]thiazinethiones

Cycloaddition of a bis[1,2]dithiolo[1,4]thiazine ketothione and mono- or bis(ferrocenecarbonyl)acetylenes under catalysis by scandium triflate gave mono- and bis-ferrocenecarbonyl-1,3-dithiolylidene[1,2]dithiolo[1,4]thiazines. Cycloaddition of a bis-dithiolothiazine dithione and bis-ferrocenylbutynedione gave 3,5-di(bis-ferrocenecarbonyl-1,3-dithiolylidene)[1,4]thiazine, a structure related to extended tetrathiafulvalenes