Mercedes Martín

CHIRAL RECOGNITION OF TARTARIC ACID DERIVATIVES WITH CHROMENONE-BENZOXAZOLE RECEPTORS AND A SPIROBIFLUORENE SPACER

Abstract The combination of a spirobifluorene spacer with two chromenone-amino-benzoxazole binding arms affords a chiral cleft type receptor. Due to the strong chiral recognition, resolution of the receptor racemic mixture can be achieved by means of a silica gel TLC plate impregnated with optically pure dibenzoyl tartaric acid. Slow complex formation on the 1 H-NMR scale with this host at −10°C allows observation of different signals for free and complex guests in 1 H-NMR.

Catalysis of nucleophilic addition of pyrrolidine to 2-(5H)-furanone through chromenone cleft-type receptors

Abstract Several H-bonding receptors are shown to significantly catalyze the nucleophilic addition of pyrrolidine to 2-(5 H )-furanone to a significant extent. Combination of these receptors with a sulfonamide group affords a further increase in the catalytic effect of these molecules.

Benzimidazole receptors for carboxylic acids

Combination of an aminobenzimidazole with a chromenone unit provides a receptor for carboxylic acids or primary amides. This host is highly selective for carboxylic acids with Kass above 106 M−1 while amides only bind weakly with association constants in the order of hundreds of M−1.

Malonic acid receptors with decarboxylative activity

Abstract The geometry and electronic properties of several malonic acids receptors are studied with a view to optimizing their decarboxylative activity.

Chromenone derivatives as receptors for N-benzoylamino acids

The chromenone derivative 5, easy to synthesize from 2-hydroxyacetophenone 1, has been used to prepare the hosts 7–10 and 12. These combine three hydrogen bonds, π-stacking and chargetransfer interactions for the complexation of N-benzoylamino acids in CDCl3.

Cleft type receptors for butenolides based on chromenone derivatives

Abstract A chromenone building block is suitable for the preparation of H-bonding lactone receptors. Combination of this fragment with a second chromenone provides a new cleft suitable for strongly association of γ-hydroxymethyl-γ-lactones.