calixarenes and resorcinol

Spatial sequestration of molecules is a prerequisite for the complexity of biological systems, enabling the occurrence of numerous, often non-compatible chemical reactions and processes in one cell at the same time. Inspired by this compartmentalization concept, chemists design and synthesize artificial nanocontainers (capsules and cages) and use them to mimic the biological complexity and for new applications in recognition, separation, and catalysis. Here, we report the formation of large closed-shell species by interactions of well-known polyphenolic macrocycles with anions. It has been known since many years that C-alkyl resorcin[4]arenes (

Topics: Anions; Calixarenes; Pyrogallol; Resorcinols

Topics: Calixarenes; Catalysis; Ethanol; Furans; Hydrochloric Acid; Phenylalanine; Reproducibility of Results; Resorcinols; Water

A novel octavalent, resorcin[4]arene derived, cross-linker designed to overcome some of the limitations of commercially available reagents is significantly more efficient for covalent stabilisation of protein-protein interactions.

Topics: Calixarenes; Cross-Linking Reagents; Dimerization; Molecular Structure; Proteins; Resorcinols

Four cone resorc[4]arene octamethyl ethers (10, 11, ent-10, and ent-11) tetrafunctionalized at the feet with valyl-leucine [LL- (6); DD- (ent-6)] and leucyl-valine [LL- (9); DD- (ent-9)] methyl esters have been synthesized. These compounds, obtained by conjugation of macrocycle tetracarboxylic acid chlorides with the appropriate terminal amino groups of the above dipeptides, are N-linked peptidoresorc[4]arenes. We found that these macrocycles (M) are capable of recognizing the homologue dipeptides as guests (G), both in solution and in the gas phase, by forming relatively stable host-guest complexes ([M.G]), resistant to chromatographic purification but not to heating. Complexation phenomena between M and G in solution were investigated by NMR methods, including NMR DOSY experiments, for the detection of translational diffusion. Heteroassociation constants of 2030 and 186 M(-1) were obtained by the Foster-Fyfe method for the complexes [10.6] and [10.ent-6], respectively, the latter being comparable to the self-association constant of dipeptide itself. Conversely, the structural features of the proton-bound complexes [M.H.Gn]+ (n = 1, 2), generated in the gas phase by electrospray ionization mass spectrometry (ESI-MS), were investigated by collision-induced dissociation (CID) experiments. In both cases, the four N-linked peptidoresorc[4]arenes were shown to act as synthetic receptors and to recognize the homologue dipeptide by means of hydrogen bonds.

Topics: Calixarenes; Carboxylic Acids; Chlorides; Hydrogen Bonding; Magnetic Resonance Spectroscopy; Models, Chemical; Peptides; Resorcinols; Spectrometry, Mass, Electrospray Ionization

The interaction of inherently chiral resorc[4]arenes with different chiral ammonium ions was measured by ESI-MS. For that purpose one enantiomer of the ammonium guests was labeled with deuterium to distinguish the enantiomers by their mass. We synthesized the ammonium salts by reaction of chiral primary amines with either CH3I or CD3I and analyzed the resulting ammonium iodides by NMR and optical rotation. The complexation experiments were performed by mixing the chiral host with various ratios of the unlabeled guest and its labeled enantiomer. By analysis of the integrals of the host-guest complexes we observed a chiral discrimination effect and a secondary isotope effect as well.

Topics: Amines; Calixarenes; Hydrocarbons; Quaternary Ammonium Compounds; Resorcinols; Spectrometry, Mass, Electrospray Ionization; Stereoisomerism