Reaction of an introverted carboxylic acid with carbodiimide

Iwasawa, Tetsuo; Wash, Paul L.; Gibson, Christoph; Rebek, Julius

doi:10.1016/j.tet.2007.03.075

Cited by 50 publications

(32 citation statements)

References 41 publications

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“…The best synthesis (in our hands) of hydrophobic introverted acid cavitands H 2a,b was recently reported,39 as has that for the water-soluble derivative H 2c 40. While the introverted acid cavitands synthesized and used in this study are racemic, it is possible to resolve the enantiomers by HPLC using a chiral column ((3 S ,4 R ) Pirkle 1J Regiscolumn, 4.6 × 250 mm, EtOH: CH 2 Cl 2 (3:97), 1.0 mL/min).…”

Section: Resultsmentioning

confidence: 89%

Interaction Energies and Dynamics of Acid−Base Pairs Isolated in Cavitands

et al. 2008

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The use of capsules and cavitands in physical organic chemistry is briefly reviewed, and their application to the study of salt bridges is introduced. Carboxylate/ammonium ion pairs are generated within an environment that more or less surrounds the functional groups within a synthetic fixed The barriers to in-out exchange of several amine guests were determined to be in the range from 15 to 24 kcal mol −1 . Some parallels with enzymes are drawn: the receptor folds around the guest species; presents them with inwardly directed functionality; and provides a generally hydrophobic environment and a periphery of secondary amide bonds.

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Section: Resultsmentioning

confidence: 89%

Interaction Energies and Dynamics of Acid−Base Pairs Isolated in Cavitands

et al. 2008

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“…Accordingly, the unstable hemiaminal dissociates to starting materials or proceeds to imine with loss of water. We arranged for this reaction to take place within a deep cavitand, and found the hemiaminal was stabilized for minutes to hours, long enough to characterize by NMR spectroscopic methods (Iwasawa et al ., 2007b). …”

Section: Reactionsmentioning

confidence: 99%

Chemistry and Catalysis in Functional Cavitands

Hooley

Rebek

2009

Chemistry & Biology

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Summary Biological macromolecules use binding forces to access unfavorable chemical equilibria and stabilize reactive intermediates by temporarily isolating them from the surrounding medium. Certain synthetic receptors, functional cavitands, share these abilities and allow the direct observation of labile intermediates by conventional spectroscopy. The cavitands feature inwardly-directed functional groups that form reversible, covalent bonds with small molecules held inside. Tetrahedral intermediates of carbonyl addition reactions – hemiaminals, hemiacetals and hemiketals – show amplified concentrations and lifetimes of minutes under ambient conditions. Labile intermediates in addition reactions of carboxylic acids to isonitriles are also stabilized by isolation in the space of the cavitands. The restricted environments channel the reactions of intermediates in cavitands along a specific path, and strengthen the parallels between functional synthetic cavitands and enzymes.

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“…Moreover, even in the desirable reaction pathway, some amount of N,N -diisopropyl urea may remain on the surface and be also observed as N 1s. [57] Thus the N A3 curve indicates both the amide and carbamide groups, and the N B2 curve indicates the amino group. The F D curve indicates the trifluoromethyl group.…”

Section: Mechanisms Of Derivatization Reactionsmentioning

confidence: 99%

X‐ray photoelectron analysis of surface functional groups on diamond‐like carbon films by gas‐phase chemical derivatization method

Takabayashi

Okamoto

Motoyama

et al. 2010

Surface & Interface Analysis

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a Oxygen-related surface functional groups on diamond-like carbon (DLC) films were derivatized with fluorine-and nitrogenrelated groups by the gas-phase chemical derivatization (GCD) method, and the groups were analyzed quantitatively by X-ray photoelectron spectroscopy (XPS). It is desirable that a derivatization reaction is unique to the target group; however, it usually causes undesirable side reactions which affect other groups. This diversity of the reactions has complicated the analysis. In this report, we have overcome the problem by applying a mathematical treatment which takes the side reactions into account. This improved analysis shows that it is no longer necessary to have derivatization reactions unique to the target groups. As a result, it is demonstrated that the carbonyl (C O) group is the dominant surface functional group on both the DLC and its wet-oxidized films, the carboxyl (COOH) group plays a minor role, and the presence of the hydroxyl (OH) group is logically denied. Considering the oxidation steps of these oxygen-related surface functional groups, it is suggested that the C O group on the DLC films requires the cleavage of the carbon-carbon bond with a relatively high activation energy barrier to change into the COOH group.

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Reaction of an introverted carboxylic acid with carbodiimide

Cited by 50 publications

References 41 publications

Interaction Energies and Dynamics of Acid−Base Pairs Isolated in Cavitands

Interaction Energies and Dynamics of Acid−Base Pairs Isolated in Cavitands

Chemistry and Catalysis in Functional Cavitands

X‐ray photoelectron analysis of surface functional groups on diamond‐like carbon films by gas‐phase chemical derivatization method

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