Q1. What are the contributions in this paper?
To diphenylglycoluril ( 2 ), four aliphatic chains were attached, each with a vanillyl alcohol group at the end this paper.
A cage compound derived from cyclotriveratrylene and diphenylglycoluril sub-units
02 Sep 2010-Recueil des Travaux Chimiques des Pays-Bas (Elsevier Science bv)-Vol. 108, Iss: 6, pp 215-218
TL;DR: To diphenylglycoluril (2), four aliphatic chains were attached, each with a vanillyl alcohol group at the end as discussed by the authors, and three of them cyclized to form a cyclotriveratrylene unit.
Abstract: To diphenylglycoluril (2), four aliphatic chains were attached, each with a vanillyl alcohol group at the end. In an acid-catalyzed reaction, three of the vanillyl alcohol groups cyclize to form a cyclotriveratrylene unit. The resulting compound (3) has a well-defined cavity and a free, func- tionalized arm. Cyclization of four vanillyl alcohol groups (5) does not occur, probably for steric reasons.
Summary (1 min read)
Introduction
- Organic molecules containing an intramolecular cavity, as well as a nearby catalytic centre, are currently receiving a great deal of attention as synthetic equivalents of enzymes (so called synzymes)1.
- In a later stage, these groups can be converted into catalytic functions (Fig. 2,A ).
- The presence of these isomers can be seen in the l3C N M R spectrum which shows more than one signal for each carbon atom of 3.
- The authors found that the ratio 3/4 depends on the reaction conditions used.
- CPK models suggest that a "sofa" form of the cyclotetraveratrylene sub-unit in 5 is not possible for steric reasons.
General
- Unless otherwise indicated, commercial materials were used as received.
- Diethyl ether, toluene and hexane were distilled from sodium ketyl, while CHC13 was distilled from CaCl2.
- FAB mass spectra were recorded on a VG ZAB 2F spectrometer (matrix: 3-nitrobenzyl alcohol).
- Ele mental analyses were carried out by the Elemental Analytical Section of the Institute for Applied Chemistry TNO, Zeist, The Netherlands.
4-(6-B rom ohexyloxy)-3-m ethoxybenzaldehyde (1)
- The crude product was crystallized from ether.
- During this addition, the temperature rose to approximately 30°C.
- The resulting mixture was stirred for 1 h, brought to pH 6 with concentrated hydrochloric acid and evaporated under reduced pressure.
- The residue was first purified by gel-permeation chromatography (Sephadex LH-20, eluent CHC13).
Did you find this useful? Give us your feedback
Citations
More filters
TL;DR: Hemmicryptophanes are revealed to be inherently chiral ditopic host compounds, able to encapsulate various guests, including charged and neutral species, and enter the field of stimuli-responsive supramolecular systems exhibiting controlled functions.
Abstract: In the wide area of host–guest chemistry, hemicryptophanes, combining a cyclotribenzylene (or cyclotriveratrylene CTV) unit with another different C3-symmetrical moiety, appears as a recent family of molecular cages. The synthesis and recognition properties of the first hemicryptophane were reported in 1982 by Collet and Lehn, but the very little attention received by this class of host compounds in the 20 years following this first promising result can account for their apparent novelty. Indeed, in the last 10 years hemicryptophanes have aroused growing interest, and new aspects have been developed. Thanks to the rigid shaping unit of the north part (CTV) and also the variable and easily functionalized south moiety, hemicryptophanes are revealed to be inherently chiral ditopic host compounds, able to encapsulate various guests, including charged and neutral species. They also enter the field of stimuli-responsive supramolecular systems exhibiting controlled functions. Moreover, endohedral functionalizati...
145 citations
TL;DR: A review of the recent developments of the chemistry of cyclotriveratrylenes and cryptophanes, and their use in the study of host-guest interactions is given in this paper.
Abstract: A review is given of the recent developments of the chemistry of cyclotriveratrylenes and cryptophanes, and of their use in the study of host-guest interactions. Experiments dealing with the complexation of tetrahedral species including neutral molecules (halogenomethanes and alkanes) and organic soft cations (tri- and tetramethyl ammonium cations, acetylcholine) are discussed. Prospective applications of cyclotriveratrylenes and cryptophanes to the design of ferroelectric liquid crystals and of three-dimensional charge tranfer materials are presented.
107 citations
TL;DR: A novel class of chiral hemicryptophane hosts has been synthesized in diastereoisomerically pure form and displayed two pairs of mirror-image CD spectra, which were used to determine their absolute configuration.
63 citations
TL;DR: The heteroditopic hemicryptophane 1, which bears a tripodal anion binding site and a cation recognition site in the molecular cavity, proved to be an efficient ion-pair receptor.
Abstract: The heteroditopic hemicryptophane 1, which bears a tripodal anion binding site and a cation recognition site in the molecular cavity, proved to be an efficient ion-pair receptor. The hemicryptophane host binds anions selectively depending on shape and hydrogen-bond-accepting ability. It forms an inclusion complex with the Me(4)N(+) ion, which can simultaneously bind anionic species to provide anion@[1⋅Me(4)N(+)] complexes. The increased affinity of [1⋅Me(4)N(+)] for anionic species is attributed to a strong cooperative effect that arises from the properly positioned binding sites in the hemicryptophane cavity, thus allowing the formation of the contact ion pair. Density functional theory calculations were performed to analyze the Coulomb interactions of the ion pairs, which compete with the ion-dipole ones, that originate in the ion-hemicryptophane contacts.
58 citations
TL;DR: Determination of the activation parameters provides evidence for a concerted, rather than a stepwise, interconversion mechanism with entropies of -243 and -272 J mol (-1) K(-1) for (P)-(S,S,Lambda)-3 and (M-S, S-S)-4, respectively.
Abstract: The diastereomeric hemicryptophane oxidovanadium(V) complexes (P)-(S,S,S)-3 and (M)-(S,S,S)-4 have been synthesized. (1)H and (51)V NMR spectra in solution are consistent with the formation of Lambda and Delta forms of the propeller-like vanatrane moiety, leading to two diastereomeric conformers for each complex: that is, (P)-(S,S,S-Lambda)-3/(P)-(S,S,S-Delta)-3 and (M)-(S,S,S-Lambda)-4/(M)-(S,S,S-Delta)-4. The Lambda/Delta ratio is rather temperature-insensitive but strongly dependent on the solvent (the de of (M)-(S,S,S)-4 changes from 0 in benzene to 92 % in DMSO). The solvent therefore controls the preferential clockwise or anticlockwise orientation of the propeller-like atrane unit. The energy barriers for the Lambdaright arrow over left arrowDelta equilibrium were determined by NMR experiments, and the highest DeltaG( not equal) value (103.7 kJ mol(-1)) was obtained for (P)-(S,S,S)-3, much higher than those reported for other atrane derivatives. This is attributed to the constraints arising from the cage structure. Determination of the activation parameters provides evidence for a concerted, rather than a stepwise, interconversion mechanism with entropies (DeltaS( not equal)) of -243 and -272 J mol(-1) K(-1) for (P)-(S,S,S)-3 and (M)-(S,S,S)-4, respectively. The molecular structure of the (P)-(S,S,S-Lambda)-3 isomer was solved by X-ray diffraction and shows a distorted structure with one of the linkers located in the CTV cavity. Complementary quantum chemical calculations were carried out to obtain the energy-minimized structures of (P)-(S,S,S)-3 and (M)-(S,S,S)-4. Our density functional theory calculations suggest that the (P)-(S,S,S-Lambda)-3 is favored, in agreement with experimental data. For the M series, a similar strategy was used to extract molecular structures and relative energies. As in the case of the P diastereomer, the Lambda form dominates over the Delta one.
45 citations
References
More filters
345 citations
TL;DR: A l'aide de la spectrometrie RMN, on etudie le dedoublement optique du bromochlorofluoromethane qui est inclus dans une cavite de compose chiral le cryptophane C.
Abstract: A l'aide de la spectrometrie RMN, on etudie le dedoublement optique du bromochlorofluoromethane qui est inclus dans une cavite de compose chiral le cryptophane C
143 citations
TL;DR: In this paper, a macro-cyclic N3O3 binding unit with a rigid cyclotriveratrylene unit via three bridges was synthesized by connecting two macropolycyclic molecules.
Abstract: Combination of a receptor unit with a rigid shaping unit produces a new type of receptor molecules of the cryptand class, hollow macropolycyclic molecules termed speleands, capable of substrate inclusion. Two members of this category of compounds 1 and 2, have been synthesized by connecting in a single step, a macro-cyclic [18]-N3O3 binding unit with a rigid cyclotriveratrylene unit via three bridges. Compound 1 binds the rnethylammonium cation forming both external and internal complexes; for the latter a ‘speleme’ structure, schematically represented by 15, may be proposed.
81 citations
73 citations
TL;DR: L'hexaaza-24-crown-8 catalyse l'hydrolyse du phosphate d'acetyle en orthophosphate and la synthese de diphosphate.
Abstract: L'hexaaza-24-crown-8 catalyse l'hydrolyse du phosphate d'acetyle en orthophosphate et la synthese de diphosphate
56 citations