Bis(diamido)‐Bridged Basket Resorcin[4]arenes as Enantioselective Receptors for Amino Acids and Amines

Abstract

On the research avenue opened by the rigidified double‐spanned resorcin[4]arene 1, we have synthesized both enantiomers of the two chiral basket resorcin[4]arenes 3 and 4, each containing two 1,2‐diaminocyclohexane and 1,2‐diphenylethylenediamine bridges, respectively. In the new compounds, the aromatic rims assume the expected flattened cone arrangement, whereas two different conformations, tentatively designated as “open wings” and “folded wings”, were attributed to the bridge substituents according to molecular modeling studies. In MSn (ESI) experiments, the proton‐bonded diastereomeric [4·H·A]+ complexes with amino acidic guests (A) exhibited a pronounced selectivity towards the enantiomers of tyrosine methyl ester (tyrOMe) and amphetamine (amph), whereas the chirality of tryptophan (trp) was ineffective. Moreover, a kinetic study on the base‐induced displacement of the guest revealed that the L‐tyrOMe (and L‐amph) enantiomer is faster displaced from the heterochiral [4·H·L‐tyrOMe]+ (or [ent‐4·H·l‐amph]+) complex than from the homochiral [ent‐4·H·L‐tyrOMe]+ (or [4·H·l‐amph]+) one. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Stereochemical Preference of 2'‐Deoxycytidine for Chiral Bis(diamido)‐bridged Basket Resorcin[4]arenes

“…The synthesis of bis(diamido)‐bridged basket resorcin[4]arene (all‐S)‐1 (Scheme ), has been reported . The host contains two rigid 1,2‐diphenylethylenediamine bridges, built by reaction of the acid chloride functionalities of two adjacent substituents with (1S,2S)‐(–)‐1,2‐diphenylethylendiamine (DPEDA).…”

Chirality Effects on the IRMPD Spectra of Basket Resorcinarene/Nucleoside Complexes

“…Cytidine (2) and its epimer cytarabine (3) were used as chiral guests because of their ability to establish stable proton bonds with the amidocarbonyl groups on the basket resorcin [4]arene. [39][40][41] For comparison, the study was also extended to cytosine (1), which was used as a simplified achiral model of compounds 2 and 3. For the sake of clarity, the functional groups that belong to the host will be given in italic.…”

Síntesis de 2,8,14,20-tetra-n-butilpirogalol[4]areno y estudio computacional conformacional

“…El producto fue aislado en forma de monocristales y analizado por difracción de rayos X. La estructura cristalina corresponde a una celda triclínica de grupo espacial P-1 que contiene dos moléculas del macrociclo por celda unitaria de dimensiones a=11.63920(10) Å, b=12.8367(2) Å, c=17.5423(2) Å y án-gulos α=104.1070 (10) o β=95.6630 (10) o γ=101.5790 (10) o . El análisis de rayos X reveló que el macrociclo corresponde a un tetrámero del pirogalol que adopta la conformación todo cis (rccc) también llamada estructura de cáliz.…”

“…Mientras que los primeros reportes sobre la existencia de macromoléculas en forma de corona o cáliz se remontan a los años 1940 [5], solo en las últimas dos déca- das se han reportado una cantidad considerable de investigaciones dedicadas a estos compuestos [6,7,8,9,10,11,12,13,14]. Igualmente, la metodología de síntesis y el control de las variables conformacionales de estas moléculas han mejorado considerablemente en los últi-mos años [15,16,17].…”

“…β=95.6630 (10) o γ=101.5790 (10) o , which contained two molecules of the tetramer related to each other by an inversion center. The solid state structure of the macrocycle shows an all cis-conformation (rccc), also called crown or cone structure, which is consistent with all other known aliphatic derivatives of pyrogallolarenes.…”