Chiroptical study of cryptophanes subjected to self-encapsulation.

In 1,1,2,2-tetrachloroethane-d , the Xe NMR spectrum of the Xe@cryptophane-223 complex bearing seven acetate groups (Xe@1 complex) shows an unusually broad signal compared with that of its congeners (Chapellet, LL. et al. J.

High-Relaxivity Gd(III)-Hemicryptophane Complex.

The polytopic hemicryptophane cage HC1 combining a cyclotriveratrylene (CTV) unit and a tris(2-aminoethyl)amine (tren) moiety connected by three 2-hydroxyisophthalamide linkers was synthesized in 12 steps. The resulting highly functionalized covalent host is soluble in aqueous medium and has been used to complex Gd(III) ion. The Gd(III)@HC1 complex presents promising relaxivity properties when compared to the clinically used Dotarem MRI agent.

Synthesis of Cryptophanes with Two Different Reaction Sites: Chemical Platforms for Xenon Biosensing.

We report the synthesis of new water-soluble cryptophane host molecules that can be used for the preparation of (129)Xe NMR-based biosensors. We show that the cryptophane-223 skeleton can be modified to introduce a unique secondary alcohol to the propylenedioxy linker. This chemical functionality can then be exploited to introduce a functional group that is different from the six chemical groups attached to the aromatic rings.

Shorter and modular synthesis of hemicryptophane-tren derivatives.

Hemicryptophanes are host molecules with many applications as supramolecular catalysts or in ion selective recognition. A very convenient and efficient modular approach for the synthesis of hemicryptophane-tren (tren, tris(2-aminoethyl)-amine) derivatives has been developed. For instance, hemicryptophane 1 was synthesized at the gram scale in four steps from vanillyl alcohol compared to the previous seven-step procedure.

Gold(I)-catalyzed cyclization of β-allenylhydrazones: an efficient synthesis of multisubstituted N-aminopyrroles.

The gold(I)-catalyzed cycloisomerization of β-allenylhydrazones provides an efficient access to multisubstituted N-aminopyrroles, which are obtained in good to excellent yields. This new intramolecular cyclization method can be applied either to alkyl- or aryl-substituted allenes. The reaction proceeds under mild conditions with short reaction times through a selective intramolecular 1,2-alkyl or -aryl migration extending the general scope of the reaction.