Nuclear magnetic resonance spectra of N-acylanilines. Effect of substituents on the chemical shift of the ortho proton

Zanger, Murray; Simons, William Walter; Gennaro, A.

doi:10.1021/jo01273a084

Cited by 28 publications

(7 citation statements)

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“…Since then, qualitative and quantitative evaluations of the effects of anisotropy on amide chemical shifts were published. [45] In the present work, an intriguing difference in the anisotropic effects between the 1D-G and 2D-G amides was found in the 1 H spectra in CDCl 3 (Table 3). While in the tertiary phenylglyoxamides 1D-G the R1 and R2 (R1 = R2) alkyl chains are magnetically nonequivalents, in the related mandelamides 2D-G these anisotropic effects are extended to the geminal hydrogens of the methylene directly bonded to the amidic nitrogen.…”

Section: Resultssupporting

confidence: 44%

Anisotropic and hydrogen bonding effects in phenylglyoxamides and mandelamides: theoretical and NMR conformational evaluation

Gonçalves

Esteves

Pinto

et al. 2008

Magnetic Reson in Chemistry

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Interesting anisotropic effects were observed for phenylglyoxamides and their respective mandelamides. Such effects were observed in experimental (1)H and (13)C NMR (in CDCl(3), CD(3)OD, and DMSO-d(6) solvents) and in some cases with good correlation to theoretical (1)H and (13)C NMR DFT-GIAO (B3LYP/6-311++G**//B3LYP/6-31G*) calculations. A systematic conformational analysis of these compounds was performed in a two-step methodology, using PM3 and DFT (B3LYP/6-31G*) calculations; with good accomplishment and computational time economy. It was observed that intramolecular hydrogen bonding plays a significant role in the conformation of such compounds. Finally, a geminal nonequivalence of an N-CH(2) moiety, in one of the alkyl side chain (R1 = R2), was found for the tertiary mandelamides studied.

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Section: Resultssupporting

confidence: 44%

Anisotropic and hydrogen bonding effects in phenylglyoxamides and mandelamides: theoretical and NMR conformational evaluation

Gonçalves

Esteves

Pinto

et al. 2008

Magnetic Reson in Chemistry

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“…All the purified ligands were characterised by MS, elemental analysis, proton and carbon NMR spectroscopies, as outlined in Table 1, and presented expected structural features. Interestingly, ligands 2 and 5 exhibits enhanced deshielding for the proton ortho to the acylamine group called "ortho effect" [20]. Ortho-substituent able of interactions with the amide hydrogen are expected to stabilise planar conformations in which anisotropic deshielding of the remaining ortho hydrogen is maximised and in which the Finally, crystals of 2 suitable for X-ray diffraction were obtained by slow evaporation of a dichloromethane solution.…”

Section: Synthesis and Structural Characterizationmentioning

confidence: 99%

New neutral and lipophilic technetium complexes based on a cytectrene moiety: synthesis, characterization and biological evaluation

Aissi¹,

Malek-Saied

Saidi

et al. 2014

Radiochimica Acta

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The synthesis, characterization and biological evaluation of five neutral and lipophilic 99m Tccomplexes, so-called cytectrenes, obtained from -substitutedferrocenecarboxamide derivatives are reported.-substitutedferrocenecarboxamide starting materials were obtained in two steps, with good yield and were fully characterized by classical spectroscopic methods including X-ray diffraction analysis for one of them.Using a microwave strategy for the 99m Tc-radiolabelling step, each cytectrene were obtained quickly (radiolabelling time < 5 min), from modest to good yield. The 99m Tc-complexes, characterized by HPLC comparison with cold rhenium complex analogues, are stable, neutral and lipophilic (log o/w ranged between 1.8 and 2.9). Unfortunately, despite such suitable features, in vivo studies of two of them gave poor results, in terms of brain uptake. Both radiocompounds exhibited the maximum brain accumulation of 0.31% ID/g and 0.26% ID/g at 5 min post-injection, respectively, followed by a very fast washout from the brain (0.06% ID/g and 0.07% ID/g at 30 min post-injection, respectively). Although our ligand systems exhibited high stability against exchange reactions with blood proteins, the high radioactivity level in stomach, increasing with time, suggests in vivo decomposition of our complex to pertechnetate.

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“…This is especially attractive for characterization, biological testing, and other uses; however, it may not necessarily represent the optimum conditions for the preparation of each individual compound. Most reagents used in the preparation are commercially available, and the substituted acetoacetanilides for 9 and 11 were prepared by one-step documented procedures (21)(22)(23). The strong-base procedure is general enough so that it is readily reproducible by someone not necessarily familiar with these techniques, and it does not require an elaborate experimental setup.…”

mentioning

confidence: 99%

“…The tetrahydrofuran (THF) was distilled from sodium (benzophenone ketyl) prior to use, and chemicals were obtained from Aldrich Chemical Co. and Pfaltz and Bauer, Inc. The acetoacetanilides, N-(4-bromophenyl)-3-oxo-butanamide and N-(4-methylphenyl)-3-oxo-butanamide, for the preparation of thiochromone-2-acetamides 9 and 11, were made by the condensation of p-bromoaniline or p-toluidine with ethyl acetoacetate (21)(22)(23).…”

mentioning

confidence: 99%

Preparation of N-aryl-4-oxo-4H-1-benzothiopyran-2-acetamides from trilithiated acetoacetanilides and lithiated methyl thiosalicylate

Angel¹,

Finefrock²,

French³

et al. 1999

Can. J. Chem.

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Acetoacetanilide and substituted acetoacetanilides were trilithiated in excess lithium diisopropylamide, and the polylithiated intermediates were regioselectively condensed with lithiated methyl thiosalicylate, followed by acid cyclization to afford substituted N-aryl-4-oxo-4H-1-benzothiopyran-2-acetamides (thiochromone-2-acetamides).Résumé : On a effectué une trilithiation de l'acétoacétanilide et d'acétoacétanilides substitués en procédant dans un excès de diisopropylamidure de lithium, et les intermédiaires polylithiés ont subi une condensation régiosélective par réaction avec du thiosalicylate de méthyle lithié, suivie d'une cyclisation acide conduisant à des N-aryl-4-oxo-4H-1-benzothiopyran-2-acétamides (thiochromon-2-acétamides).Mots clés : thiochromones; synthèse, base forte anion multiple; condensation du type de Claisen.

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Nuclear magnetic resonance spectra of N-acylanilines. Effect of substituents on the chemical shift of the ortho proton

Cited by 28 publications

References 0 publications

Anisotropic and hydrogen bonding effects in phenylglyoxamides and mandelamides: theoretical and NMR conformational evaluation

Anisotropic and hydrogen bonding effects in phenylglyoxamides and mandelamides: theoretical and NMR conformational evaluation

New neutral and lipophilic technetium complexes based on a cytectrene moiety: synthesis, characterization and biological evaluation

Preparation of N-aryl-4-oxo-4H-1-benzothiopyran-2-acetamides from trilithiated acetoacetanilides and lithiated methyl thiosalicylate

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