Methylene-Bridged Glycoluril Dimers:  Synthetic Methods

Wu, An‐Xin; Chakraborty, Arindam; Witt, Dariusz; Lagona, Jason; Damkaci, Fehmi; Ofori, Marie A; Chiles, Jessica K; Fettinger, James C.; Isaacs, Lyle

doi:10.1021/jo0258958

Cited by 106 publications

(114 citation statements)

References 61 publications

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“…It seemed likely that if the CB[n] family could be modified to improve their solubility in organic media, to alter the size and shape of the cavity, and to provide different functional groups that interact directly with guests then the range of potential applications of the CB[n] family would be dramatically expanded. The following sections describe the approaches that we, [245][246][247][248][249] and others, [8,90,201,[250][251][252][253][254] have taken toward alleviating these potential limitations.…”

Section: Cb[n] Familymentioning

confidence: 99%

The Cucurbit[n]uril Family

et al. 2005

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In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed "cucurbituril" by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants--the pumpkin. In the intervening years, the fundamental binding properties of CB[6]-high affinity, highly selective, and constrictive binding interactions--have been delineated by the pioneering work of the research groups of Mock, Kim, and Buschmann, and has led to their applications in waste-water remediation, as artificial enzymes, and as molecular switches. More recently, the cucurbit[n]uril family has grown to include homologues (CB[5]-CB[10]), derivatives, congeners, and analogues whose sizes span and exceed the range available with the alpha-, beta-, and gamma-cyclodextrins. Their shapes, solubility, and chemical functionality may now be tailored by synthetic chemistry to play a central role in molecular recognition, self-assembly, and nanotechnology. This Review focuses on the synthesis, recognition properties, and applications of these unique macrocycles.

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Section: Cb[n] Familymentioning

confidence: 99%

The Cucurbit[n]uril Family

et al. 2005

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“…7,8 The improved solubility of CB [7] and the spacious cavity of CB [8] heterodimers as a mixture of S-shaped and C-shaped diastereomers. 191,192 To rationalize the selective formation of C-shaped heterodimers, we studied the mechanism of the interconversion of II-1 and II-2. We discovered that the S-shaped to C-shaped isomerization was an intramolecular process that occurs with retention of configuration (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…Compounds II-1 and II-2 were prepared by literature procedures. 191,192 TLC analysis was performed using pre-coated glass plates from E. Merck. Column chromatography was performed using silica gel (230-400 mesh, 0.040-0.063 m) from E. Merck using eluents in the indicated v:v ratio.…”

Section: Synthetic Procedures and Characterizationmentioning

confidence: 99%

Cucurbit[n]uril Analogues.

2004

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Molecular recognition and self-assembly in aqueous solution have experienced rapid growth in recent years. The use of -, -, and -cyclodextrins, calixarenes, and cyclophanes have served as the platforms for molecular recognition in aqueous solution. Recently, the investigation of an alternative platform based on cucurbituril has become the focus of several research groups. The rigid structure and capability of forming complexes with molecules and ions through hydrophobic, iondipole and hydrogen-bonding interactions make cucurbituril an attractive candidate as a synthetic receptor as well as a building block for the construction of supramolecular architectures.However, before cucurbituril can be used to supplant the more common platforms as the molecule of choice for molecular recognition and self-assembly in aqueous solution, several advances must be made: 1) cucurbiturils must become available in a variety of sizes, 2) their solubility must be improved, and 3) synthetic procedures must be advanced to include the ability to selectively generate specific cucurbituril homologues, derivatives, and analogues. To help rationalize the high yields obtained in these macrocyclization reactions, we performed mechanistic studies of model methylene bridged glycoluril dimers.The molecular recognition properties of a water soluble cucurbit[6]uril analogue in aqueous buffer toward a variety of guests including alkanediamines, aromatics, amino acids, and nucleobases were studied by fluorescence spectroscopy.For the alkanediamines studied, as the length of the alkane is increased between the amines, the association constants also increase. The CB [6] analogue is capable of forming strong complexes with guests containing aromatic rings with association constants (K a ) ranging from 10 2 to 10 6 M -1 due to the favorable -interactions that occur between the host and the aromatic portion of the guest while encapsulated in its hydrophobic cavity. CUCURBIT[N]URIL ANALOGUES

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“…For the preparation of compounds II-1 -II-6, we used the previously reported dinitro compounds II-12 and (±)-II-13 as starting materials. 17,20 The separate catalytic hydrogenation of II-12 and (±)-II-13 to the corresponding air-sensitive diamines …”

Section: Synthesis Of the Molecular Clips Bearing H-bonding Groups Onmentioning

confidence: 99%

Complex Self‐Sorting Systems

Ghosh

2009

Dynamic Combinatorial Chemistry

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Over the past century scientists have taken a reductionist approach towards much of the physical and biological sciences. More recently scientists have become interested in constructing complex systems from their components and thereby controlling their emerging behaviors. As supramolcular chemists we have been pursuing an approach to the creation of complex functional systems -systems chemistry -by preparation of self-sorting systems. Self-sorting system displays ability to efficiently distinguish between self-and non-self even within complex mixture. This dissertation is divided into four chapters that describe increasingly complex self-sorting systems.Chapter 1 describes a literature review on self-sorting. First, we introduced the concept of self-sorting and then described the previously studied self-sorting phenomenon in the Isaacs group followed by a description of the examples of selfsorting systems in the literature.Chapter 2 describes the synthesis and characterization of eleven C-shaped methylene bridged glycoluril dimers (II-1 -II-11) bearing H-bonding groups on their aromatic rings. Compounds II-1, II-2, (±)-II-4a, (±)-II-5, and II-7 form tightly associated homodimers in CDCl 3 due to π -π and H-bonding interactions.Compounds II-2, (±)-II-5 and II-7, having disparate spatial distribution of their Hbonding groups show the ability to efficiently distinguish between self and non-self within three component mixtures in CDCl 3 . The effect of various structural modifications (e.g. chirality, side chain steric bulk, relative orientation, number and pattern of H-bonds) on the strength of self-assembly and the fidelity of self-sorting are presented.Chapter 3 describes the stepwise construction of an 8-component self-sorted system (III-1 -III-8) by the sequential addition of components. This process occurs via a large number of states (2 8 = 256) and even a larger number of pathways (8! = 40320). A pathway (III-5, III-6, III-7, III-8, III-4, III-3, III-2, then III-1) that is self-sorted at every step along the way. Another pathway (III-1, III-8, III-3, III-5, III-4, III-7, III-2, then III-6) exhibits interesting shuttling of guest molecules among hosts. The majority of pathways -unlike the special ones described above -proceed through several non self-sorted states. We characterized the remainder of the 40320 pathways by simulation using GEPASI and describe the influence of concentration, mean binding constants and standard deviation on the fidelity of the self-sorting pathways.Chapter 4 describes a method to control biological catalysis using synthetic self-sorting systems. We report the synthesis of IV-1 -IV-5 which contain both enzyme inhibitor and cucurbit[n]uril binding domains. The enzyme binding domains of IV-1 -IV-5 bind to the active sites of Bovine Carbonic Anhydrase or Acetylcholinesterase and inhibit their catalytic activities. Addition of CB [7] catalyzes the dissociation of IV-1 and IV-2 from the active site of BCA and thereby regenerates the enzymatic activity. In contrast, addition of CB [7] to...

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Methylene-Bridged Glycoluril Dimers: Synthetic Methods

Cited by 106 publications

References 61 publications

The Cucurbit[n]uril Family

The Cucurbit[n]uril Family

Cucurbit[n]uril Analogues.

Complex Self‐Sorting Systems

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