ChemInform Abstract: STUDY OF CONFORMATIONS OF IMIDAZOLE‐ AND PYRAZOLECARBOXYLIC ACID DIAMIDES

Aleksandrova, I. Ya.; Goldfarb, Valentina; Khromov‐Borisov, N. V.; Brovtsyna, N. B.

doi:10.1002/chin.197637047

Cited by 3 publications

(6 citation statements)

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“…Intramolecular hydrogen bonding is important to the solution [64][65][66] and solid state conformations of I45DCs and their amide-ester analogues. The intermolecular hydrogen-bonding motifs formed in these compounds are reasonably reliable although certainly not entirely predictable at this time.…”

Section: Discussionmentioning

confidence: 99%

“…Both I45DCs and amideester analogues are known to form strong intramolecular hydrogen bonds in solution. [64][65][66] However, there is little detailed structural information known about these compounds in the solid state with only crystal structures of ring-alkylated derivatives having been reported. 67,68 Imidazole-4,5-dicarboxylic acid itself has been used as a cocrystallization agent with amino acids.…”

Section: Introductionmentioning

confidence: 99%

“…The properties and biological activities of I45DCs and analogues are expectedly dependent upon the structure of the molecule including any intra- and intermolecular hydrogen-bonding patterns. Both I45DCs and amide-ester analogues are known to form strong intramolecular hydrogen bonds in solution. − However, there is little detailed structural information known about these compounds in the solid state with only crystal structures of ring-alkylated derivatives having been reported. , Imidazole-4,5-dicarboxylic acid itself has been used as a cocrystallization agent with amino acids …”

Section: Introductionmentioning

confidence: 99%

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Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Baures

Rush

Wiznycia

et al. 2002

Crystal Growth & Design

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Diamide and amide-ester derivatives of imidazole-4,5-dicarboxylic acid form reliable hydrogen-bonding motifs in the solid state. The crystal structures of symmetrically substituted and dissymmetrically substituted diamides as well as amide-ester combinations were analyzed in order to identify the intermolecular hydrogen-bonding patterns. An intramolecular seven-membered hydrogen-bonded conformation forms in all derivatives where the possibility existed due to the functionality present. The motifs observed for the diamides include intermolecular NH···O and NH···N hydrogen-bonded dimers, with the exceptions to these motifs occurring in compounds having benzylamine substituents. The amines with a higher classification (i.e., 3° > 2° > 1°) in the dissymmetrically substituted diamides are the intramolecular hydrogen bond donors in the solid state, consistent with the capacity of the alkyl group to stabilize developing carbocation character resulting from bond polarization. The amide-ester derivatives also form an intramolecular hydrogen bond and an intermolecular motif based on NH···N and two different C2−H···O hydrogen bonds. A pyrrole amide-ester derivative forms an intramolecular NH···O hydrogen bond in the solid state and an intermolecular NH···O hydrogen-bonded chain. With the exception of the benzylamine-substituted diamides, the intermolecular hydrogen-bonded motifs appear reliable for these imidazole-4,5-dicarboxylic acid derivatives and will be useful in the design of analogues for specific applications.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Baures

Rush

Wiznycia

et al. 2002

Crystal Growth & Design

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“…Earlier work has shown that the I45DCs form a robust seven-membered intramolecular hydrogen bond in the solid state, along with a relatively small number of different intermolecular aggregation motifs . The solution conformation of I45DCs and other closely related analogues such as ring alkylated I45DCs has been previously reported. − The torsional potential of the substituent amide bond of a ring alkylated I45DC was estimated to be worth 20 kcal/mol, a value that reflects the strength of this intramolecular hydrogen bond . Despite this interest in the intramolecular hydrogen-bonded conformation, no empirical determination of the hydrogen bond strength has ever been reported.…”

mentioning

confidence: 99%

Intramolecular Hydrogen Bond Strength and pK_a Determination of N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

Rush

Yang

et al. 2004

Org. Lett.

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N,N'-Disubstituted imidazole-4,5-dicarboxamides (I45DCs) form an intramolecular hydrogen bond worth an estimated 14 +/- 1 kcal/mol, as measured with a model structure in DMSO-d6 at 3 mM, thereby predisposing the molecular conformation to a folded rather than extended form. The I45DCs also show evidence of aggregation in both CDCl3 (>1 mM) and DMSO-d6 (>10 mM) solutions. These compounds are uncharacteristically weak bases in comparison with imidazoles bearing similar electron-withdrawing groups.

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“…In addition to the previously described syntheses of I45DCs in the literature, ,, examples of mixed acid-amide or ester-amide functional group combinations substituted at the 4- and 5-positions of the imidazole ring have been reported. 6a, We report herein an improved synthesis of the dissymmetrically disubstituted I45DCs undertaken as part of a research effort to further explore the structure and function of these compounds. Symmetrically disubstituted I45DCs are naturally dissymmetric both by the tautomeric form of the imidazole ring as well as by the consequence of an intramolecular hydrogen bonded conformation that forms preferentially in these compounds. ,11e, However, for the purposes of this paper, the term dissymmetric refers to the relative identity of the two carboxamide substitutents.…”

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confidence: 99%

An Improved Method for the Synthesis of Dissymmetric N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

Wiznycia

Baures

2002

J. Org. Chem.

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Symmetrically and dissymmetrically disubstituted imidazole-4,5-dicarboxamides (I45DCs) have diverse bioactivities and therefore represent useful small molecules for lead structure identification in drug discovery. For this reason, an improved synthesis was developed as a first step in the preparation of greater numbers of analogues. The method involves the transformation of imidazole-4,5-dicarboxylic acid into dissymmetrically disubstituted I45DCs in four steps and in a minimum yield of 51%. This reflects an overall reduction of one synthetic step and a greater than 30% improvement in yield over the known method.

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ChemInform Abstract: STUDY OF CONFORMATIONS OF IMIDAZOLE‐ AND PYRAZOLECARBOXYLIC ACID DIAMIDES

Cited by 3 publications

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Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Intramolecular Hydrogen Bond Strength and pK_a Determination of N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

An Improved Method for the Synthesis of Dissymmetric N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

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ChemInform Abstract: STUDY OF CONFORMATIONS OF IMIDAZOLE‐ AND PYRAZOLECARBOXYLIC ACID DIAMIDES

Cited by 3 publications

References 0 publications

Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Intramolecular Hydrogen Bonding and Intermolecular Dimerization in the Crystal Structures of Imidazole-4,5-dicarboxylic Acid Derivatives

Intramolecular Hydrogen Bond Strength and pKa Determination of N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

An Improved Method for the Synthesis of Dissymmetric N,N‘-Disubstituted Imidazole-4,5-dicarboxamides

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Intramolecular Hydrogen Bond Strength and pK_a Determination of N,N‘-Disubstituted Imidazole-4,5-dicarboxamides