1,2-Diaryl-2-imidazolines. A structure–basicity relationship: application of the Hammett equation

Fernández, Beatriz; Perillo, Isabel A.; Lamdan, Sámuel

doi:10.1039/p29730001371

Cited by 25 publications

(13 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electron releasing groups on N1 aryl increase basicity of compounds 1, by favouring N1 lone pair delocalization on 895 Jul-Aug 2001 the amidine system (structure B, Figure 1), while electron withdrawing groups decrease it by delocalization on the aryl group (structure A). This behaviour was observed for other cyclic [5,6] and acyclic [7] amidines. In order to quantify these effects, the Hammett relationship [8] (Equation 1) was applied [9], log K a /K 0 = ρ.σ (1) rendering a slope value ρ=1.50 (r=0.9898, s=0.63).…”

Section: Resultssupporting

confidence: 68%

“…Compounds 1 showed a stronger basicity than the corresponding arylamines (Table II), as it was previously observed for 1H-4,5-dihydroimidazoles 3 [5] and 1,4,5,6-tetrahydropyrimidines 2 [6]. These results confirmed protonation at N3 to give the resonance stabilized amidinium cation (1H + ), since if N1-protonation occurred, basicity should be similar or lower than that of the corresponding arylamines.…”

Section: Introductionsupporting

confidence: 87%

“…This behaviour was observed for other cyclic [5,6] and acyclic [7] amidines. In order to quantify these effects, the Hammett relationship [8] (Equation 1) was applied [9], log K a /K 0 = ρ.σ (1) rendering a slope value ρ=1.50 (r=0.9898, s=0.63).…”

Section: Introductionmentioning

confidence: 52%

See 2 more Smart Citations

1H‐4,5,6,7‐Tetrahydro‐1,3‐diazepines. part II: basicity and hydrolysis of 1, 2‐diaryl derivatives

Hedrera

Perillo

Fernández

2001

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

Basicity and alkaline hydrolysis of 1,2-diaryl-1H-4,5,6,7-tetrahydro-1,3-diazepines 1 are studied. Results are analyzed on the basis of Hammett and Swain-Lupton constants, finding good structure-basicity correlation when both, inductive and mesomeric effects, are considered together. Regioselectivity is observed in the alkaline hydrolysis of compounds 1, and it is analyzed in light of the stereoelectronic control theory. Results are compared with those previously obtained for five and six membered ring homologues: 1H-4,5-dihydroimidazoles and 1,4,5,6-tetrahydropyirimidines respectively.

show abstract

Section: Resultssupporting

confidence: 68%

Section: Introductionsupporting

confidence: 87%

See 1 more Smart Citation

1H‐4,5,6,7‐Tetrahydro‐1,3‐diazepines. part II: basicity and hydrolysis of 1, 2‐diaryl derivatives

Hedrera

Perillo

Fernández

2001

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

show abstract

“…This reflects the lower basicity of oxazolines compared with their structurally related imidazoline counterparts. [27] To determine the influence of the anchoring point of the anionic borate moiety on the properties of the precatalysts, iridium complex 34 was prepared as an example of class C complexes (Scheme 5). …”

Section: Wwwchemeurjorgmentioning

confidence: 99%

Zwitterionic Iridium Complexes with P,N‐Ligands as Catalysts for the Asymmetric Hydrogenation of Alkenes

Franzke

Pfaltz

2011

Chemistry A European J

View full text Add to dashboard Cite

Several zwitterionic iridium complexes based on chiral P,N-ligands with imidazoline or oxazoline donors and anionic tetraarylborate or aryltrifluoroborate substituents have been synthesized. The corresponding cationic analogues have also been prepared, to evaluate the effect of the covalent linkage between the anion and the cationic metal complex in catalytic reactions. The respective pairs of structurally analogous precatalysts have been compared for their efficacies in the asymmetric hydrogenation of unfunctionalized olefins. In most cases, the anionic derivatization has virtually no influence on the asymmetric induction of the iridium complex. This is in accordance with X-ray structural studies, which have shown that the chiral environment of the cationic metal center is not affected by the anionic substituent. Depending on the nature of the counterion employed, the zwitterionic catalysts proved to be significantly more reactive than their cationic counterparts in nonpolar solvents.

show abstract

“…This would suggest similar mechanisms are likely for the deamination reactions of all amidine and nucleobase derivatives. Also, nucleobases and their derivatives have the potential to exist in several keto−enol or imino−amino tautomeric forms, [1][2][3][4][5][7][8][9][10][11][12] and such tautomeric distribution has a major effect on deamination reactions of these molecules. The spontaneous deamination of nucleobases is a source of DNA mutations.…”

Section: Introductionmentioning

confidence: 99%

Hydrolytic deamination reactions of amidine and nucleobase derivatives

Uddin

Alrawashdeh

Henry

et al. 2019

Int J of Quantum Chemistry

View full text Add to dashboard Cite

Amidines share the same N C─N building framework with many essential biochemical substances. In this work, we present a comparative mechanistic study on the deamination reactions of 19 amidine and nucleobase derivatives by the use of density functional theory. All the computations are performed at the B3LYP/6-31G(d,p) level in the gas phase and with the polarizable continuum model (PCM). Mechanisms of 2-and 3-step pathways including six-or eight-membered ring transition states were explored. Our results show that the overall activation energies for the deamination of amidine derivatives are close to those of nucleobase derivatives of the saturated C5─C6 bond, and lower than those of nucleobase derivatives of the unsaturated C5─C6 bond, while purine derivatives have the highest activation energies among all the derivatives studied. The 3-step mechanism gives results that are more consistent with the available experimental data than the 2-step mechanism. Based on the results of our current and previous work, we believe that the 3-step mechanism is the most likely mechanism for the hydrolytic deamination reactions of amidine and nucleobase derivatives.

show abstract

1,2-Diaryl-2-imidazolines. A structure–basicity relationship: application of the Hammett equation

Cited by 25 publications

References 0 publications

1H‐4,5,6,7‐Tetrahydro‐1,3‐diazepines. part II: basicity and hydrolysis of 1, 2‐diaryl derivatives

1H‐4,5,6,7‐Tetrahydro‐1,3‐diazepines. part II: basicity and hydrolysis of 1, 2‐diaryl derivatives

Zwitterionic Iridium Complexes with P,N‐Ligands as Catalysts for the Asymmetric Hydrogenation of Alkenes

Hydrolytic deamination reactions of amidine and nucleobase derivatives

Contact Info

Product

Resources

About