Solvent and Substituent Size Influence on the Cyclochiral Rigidity of Aminomethylene Derivatives of Resorcin[4]arene.

Resorcin[4]arenes (R[4]A) are a group of macrocyclic compounds whose peculiar feature is the presence of eight hydroxyl groups in their structure. The directional formation of intramolecular hydrogen bonds with their participation leads to the formation of a cyclochiral racemic mixture of these compounds. Their stability strongly depends on the substituent and especially the environment in which they are located.

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on structure, and theoretical calculations of non-covalent interactions.

Resorcin[4]arenes (R[4]A) are macrocyclic compounds with a cavity structure. Despite a relatively small cavity, these compounds are capable of forming complexes with small organic molecules. The current paper focuses on the synthesis of complexes between R[4]A and secondary aliphatic amines (sec-amines).

New insights into the reactivity of aminomethylene derivatives of resorc[4]arene: amine group transfer, conformational analysis, reaction mechanism.

Using the example of aminomethylene derivatives of resorc[4]arene and their Michael reaction with 4-hydroxycoumarin, the possibility of transferring an amine molecule from substrate to product is demonstrated. The conformation of the aminocoumarin derivatives of resorc[4]arene formed is controlled by the polarity of the solvent. For one of the products, conformational analysis was performed by kinetic sampling using metadynamics (MTD).

Theoretical calculations of formation and reactivity of -quinomethide derivatives of resorcin[4]arene with reference to empirical data.

This paper describes theoretical reaction pathways of alkoxybenzyl derivatives of resorcin[4]arene leading to the formation of -quinomethide derivatives of resorcin[4]arene (QMR[4]A). For each case, the activation energies for the formation of one -QMR[4]A unit and the activation energies for the backward reaction were calculated. Based on the calculated reaction pathways, the reaction mechanism of -QMR[4]A formation was proposed.

Enaminone Substituted Resorcin[4]arene-Sealing of an Upper-Rim with a Directional System of Hydrogen-Bonds.

The paper presents the synthesis of an enaminone resorcin[]arene via a thermally activated -quinomethide. The crystal structure indicates that in the solid state all enaminone units participate in a unidirectional seam of 12 intramolecular hydrogen bonds that are formed around the cavity. The molecule exhibits symmetry, with two opposite-laying enaminone units directed inside the cavity (""), and the other two units outside the cavity ("").

Intramolecular Hydrogen Bond Driven Conformational Selectivity of Coumarin Derivatives of Resorcin[4]arene.

In this study, the synthesis and structure of 4-aminocoumarin derivatives of resorcin[4]arene were investigated. Spectroscopic analysis and quantum mechanical calculations showed that this molecule undertakes a crown- conformation in chloroform. The conformations of the aminocoumarin derivative of resorcin[4]arene were compared with a hydroxycoumarin derivative of resorcin[4]arene, and the effect of the substituent on the conformational selectivity of the coumarin derivatives of resorcin[4]arene was demonstrated.

Synthesis of a coumarin derivative of resorcin[4]arene with solvent-controlled chirality.

This paper presents the synthesis of a coumarin derivative of resorcin[4]arene (1) using a cascade thermolysis/Michael reaction. The influence of the hydrogen bonding system on the conformational rigidity and cyclochirality of the coumarin derivative of resorcin[4]arene was discussed; these properties depended on the proton-donor-acceptor properties of the solvent. Significant differences, which depended on the environment, in the coumarin derivative of resorcin[4]arene fluorescence were observed and discussed.

The Inverse Demand Oxa-Diels-Alder Reaction of Resorcinarenes: An Experimental and Theoretical Analysis of Regioselectivity and Diastereoselectivity.

The Diels-Alder reaction enables introduction of new functionalities onto the resorcinarene skeleton with simultaneous generation of new stereogenic centers and expansion of the internal cavity. We present highly regio- and diastereoselective inverse electron demand oxa-Diels-Alder reactions of resorcinarene ortho-quinone methide with benzofuran and indene, each generating 12 new stereogenic centers. The mechanism and reasons for regioselectivity and diastereoselectivity were analyzed using theoretical calculations (NBO charges, Fukui functions, transition state energies, and thermodynamic stability of the products).

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review.

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures.

Synthesis and characterization of a novel resorcinarene-based stationary phase bearing polar headgroups for use in reversed-phase high-performance liquid chromatography.

A novel silica-bonded stationary phase containing a functionalized resorcinarene selector was prepared by a straightforward synthesis. The complete modification of all resorcinic hydroxyl groups was achieved by reaction with isopropyl isocyanate. The derivatized resorcinarene selector was subsequently immobilized via the four alkenyl chains containing a terminal double bond by a free radical-induced reaction on mercaptopropyl-functionalized silica.