Intermolecular N–H<sup>...</sup>O hydrogen bonds assisted by resonance. Heteroconjugated systems as hydrogen-bond-strengthening functional groups

Bertolasi, Valerio; Gilli, Paola; Ferretti, Valeria; Gilli, Gastone

doi:10.1107/s0108768195004009

Cited by 102 publications

(50 citation statements)

References 23 publications

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“…[21] As an interesting peculiarity of the molecular structure 9a, one should note the strong [15] intramolecular H bond N(4)ϪH(41)···O(4) ''assisted by resonance''. [22] n the case of compound 7b, with the more lipophilic hexafluoropropyl substituent, treatment with ammonia proceeded in solution to give at least three products even with only 2 equiv. of ammonia (1 equiv.…”

Section: Resultsmentioning

confidence: 99%

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

et al. 2002

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Section: Resultsmentioning

confidence: 99%

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

et al. 2002

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“…First, in the aromatic systems, conformational constraints due to the presence of bulky and rigid planar ring systems can diminish the opportunity for intra-and intermolecular H-bonding interactions among substituent groups both in crystals and in solution. On the other hand, resonance-assisted H-bonding can be very strong between aromatic systems containing H-donors and H-acceptors [40]. Indeed, conformational constraint effects exist in 33% of non-aromatic compounds; however, it is a substantially smaller factor than with the aromatics.…”

Section: Hmaxmentioning

confidence: 98%

No Title

Votano¹,

Parham²,

Hall

et al. 2004

Chemistry & Biodiversity

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Several QSPR models were developed for predicting intrinsic aqueous solubility, S(o). A data set of 5,964 neutral compounds was sub-divided into two classes, aromatic and non-aromatic compounds. Three models were created with different methods on both data sets: two regression models (multiple linear regression and partial least squares) and an artificial neural network model. These models were based on 3343 aromatic and 1674 non-aromatic compounds for training sets; 938 compounds were used in external validation testing. The range in -log S(o) is -1.6 to 10. Topological structure descriptors were used with all models. A genetic algorithm was used for descriptor selection for regression models. For the artificial neural network (ANN) model, descriptor selection was done with a backward elimination process. All models performed well with r2 values ranging 0.72 to 0.84 in external validation testing. The mean absolute errors in validation ranged from 0.44 to 0.80 for the classes of compounds for all the models. These statistical results indicate a sound ANN model. Furthermore, in a comparison with eight other available models, based on predictions using a validation test set (442 compounds), the artificial neural network model presented in this work (CSLogWS) was clearly superior based on both the mean absolute error and the percentage of residuals less than one log unit. In the ANN model both E-State and hydrogen E-State descriptors were found to be important.

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“…The amide N-H group in 1 is double proton donor and participate also in the formation of the intermolecular hydrogen bonds of the N-H · · · O type forming characteristic supramolecular synthons N-H · · · O=C for amide group (N1 · · · O1 2.980(3) Å) [17][18][19][20][21][22][23][24]. In this way, molecules are connected through the formation of C(4) infinite chains spreading along c-axis.…”

Section: Crystal Structure Descriptionmentioning

confidence: 99%

Potentially biologically active new substituted anilides of benzo[2,3-b]thiophene series

2007

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New substituted anilides of the heterocyclic series 2, 4, 5, 6, 7 together with the earlier described compounds 1 and 3 J Med Chem 48:2346), were synthesized from the corresponding heterocyclic carbonyl chlorides, methoxycarbonyl-and cyano-substituted anilines. Compounds 2 and 7 were prepared by methylation with methyl-iodide on the amide and the pyridine nitrogen. The Pinner reaction was used in the preparations of amidinosubstituted compounds. It seems that all the prepared compounds could be biologically interesting, especially amidinosubstituted anilides prepared in the form of water-soluble hydrochlorides or hydroiodides.Molecular and crystal structures of the three compounds, namely, 4 -methoxycarbonyl-N-phenyl-3-chloro benzo[b]thiophene-2-carboxamide (1), N-(4 -amidinophe nyl)-3-chlorobenzo[b]thiophene-2-carboxamide hydrochloride monohydrate (4) and 1-methyl-N-(4-amidinophenyl)-3-pyridine carboxamide iodide hydroiodide (7) have been determined by X-ray single-crystal diffractometry in the solid state. Compounds 1, 4 and 7 are not planar and the amide group (C=O in relation to NH group) is in trans position in all three compounds. The 3-chlorobenzo[b]thiophene moiety in 1 and 4 is oriented with the chloro substituent in cis position in relation to amide NH group. The conformational charac-

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Intermolecular N–H^...O hydrogen bonds assisted by resonance. Heteroconjugated systems as hydrogen-bond-strengthening functional groups

Abstract: The crystal structures of seven compounds forming intermolecular N--H..-O hydrogen bonds connected by 7r-conjugated systems are reported: (

Cited by 102 publications

References 23 publications

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

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Potentially biologically active new substituted anilides of benzo[2,3-b]thiophene series

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Intermolecular N–H...O hydrogen bonds assisted by resonance. Heteroconjugated systems as hydrogen-bond-strengthening functional groups

Abstract: The crystal structures of seven compounds forming intermolecular N--H..-O hydrogen bonds connected by 7r-conjugated systems are reported: (

Cited by 102 publications

References 23 publications

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

Treatment of Polyfluoro-1,1-dihydroalkyl Sulfones with Sodium Cyanate and Triethylamine: A New Method for the Synthesis of 6-(Polyfluoroalkyl)uracils

No Title

Potentially biologically active new substituted anilides of benzo[2,3-b]thiophene series

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Intermolecular N–H^...O hydrogen bonds assisted by resonance. Heteroconjugated systems as hydrogen-bond-strengthening functional groups