Synthesis and Electrochemical Behavior of Some 1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles

Costea, L. V.; Bercean, Vasile; Badea, Valentin; Gerdes, Klaus; Jordis, Ulrich

doi:10.1007/s00706-005-0469-6

Cited by 9 publications

(4 citation statements)

References 7 publications

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“…The electron-withdrawing substituents (−F, −Cl, −CF 3 , and −NO 2 ) in [Cu(PPP4FpT)Cl], [Cu(PPP4ClpT)Cl], Cu(PPP4TFpT)Cl], and [Cu(PPP4NpT)Cl], led to Cu(II/I) couples of −739, −694, −682, and −660 mV, respectively, that correlated to the increasing order of substituent electron-inductive effect, namely, F < Cl < CF 3 < NO 2 (Figure B; Table ). Similarly to the Fe(III) complexes, the redox potentials of the Cu(II) complexes varied linearly ( r = 0.77) with the σ p (Figure S4B).…”

Section: Resultsmentioning

confidence: 96%

“…The electron-withdrawing substituents (−F, −Cl, −CF 3 , and −NO 2 ) in [Fe(PPP4FpT) 2 ] + , [Fe(PPP4ClpT) 2 ] + , [Fe(PPP4TFpT) 2 ] + , and [Fe(PPP4NpT) 2 ] + , which decrease electron density around the metal center, ,, led to higher Fe(III/II) couples of −328, −309, −278, and −231 mV, respectively, compared to [Fe(PPP4pT) 2 ] +/0 (Figure A; Table ). The latter increase in redox potential correlates to the increasing order of substituent electron-inductive effects, namely, F < Cl < CF 3 < NO 2 . Furthermore, the redox potentials of the Fe(III) complexes varied linearly ( r = 0.99) with the Hammett substituent parameter ( σ p ) (Figure S4A) that measures the inductive and resonance effects of substituents on aromatic rings. , Higher positive σ p values resulted in complexes with higher potentials (Table ).…”

Section: Resultsmentioning

confidence: 99%

“…The latter increase in redox potential correlates to the increasing order of substituent electron-inductive effects, namely, F < Cl < CF 3 < NO 2 . 74 Furthermore, the redox potentials of the Fe(III) complexes varied linearly (r = 0.99) with the Hammett substituent parameter (σ p ) (Figure S4A) that measures the inductive and resonance effects of substituents on aromatic rings. 75,76 Higher positive σ p values resulted in complexes with higher potentials (Table 1).…”

Section: Journal Of Medicinalmentioning

confidence: 99%

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Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure–Activity Relationships of the Novel PPP4pT Series

Wijesinghe,

Kaya,

Gonzálvez

et al. 2023

J. Med. Chem.

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The di-2-pyridylketone thiosemicarbazones demonstrated marked anticancer efficacy, prompting progression of DpC to clinical trials. However, DpC induced deleterious oxy-myoglobin oxidation, stifling development. To address this, novel substituted phenyl thiosemicarbazone (PPP4pT) analogues and their Fe(III), Cu(II), and Zn(II) complexes were prepared. The PPP4pT analogues demonstrated potent antiproliferative activity (IC50: 0.009–0.066 μM), with the 1:1 Cu:L complexes showing the greatest efficacy. Substitutions leading to decreased redox potential of the PPP4pT:Cu(II) complexes were associated with higher antiproliferative activity, while increasing potential correlated with increased redox activity. Surprisingly, there was no correlation between redox activity and antiproliferative efficacy. The PPP4pT:Fe(III) complexes attenuated oxy-myoglobin oxidation significantly more than the clinically trialed thiosemicarbazones, Triapine, COTI-2, and DpC, or earlier thiosemicarbazone series. Incorporation of phenyl- and styryl-substituents led to steric blockade, preventing approach of the PPP4pT:Fe(III) complexes to the heme plane and its oxidation. The 1:1 Cu(II):PPP4pT complexes were inert to transmetalation and did not induce oxy-myoglobin oxidation.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Journal Of Medicinalmentioning

confidence: 99%

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Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure–Activity Relationships of the Novel PPP4pT Series

Wijesinghe,

Kaya,

Gonzálvez

et al. 2023

J. Med. Chem.

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“…The limited synthetic methods for such systems fall into three groups: (i) starting from substituted pyrazolo derivatives such as 3-amino, , 3-hydrazino, ,− 3-hydroxy or 3-diazonium salts, , (ii) cyclic condensations of 4-amino-5-thioxo-1,2,4-triazoles, 3,4-diamino-1,2,4-triazoles, , 3-methylthio-1,2,4-triazolium salts or 4-amino-1,2,4-triazolium salts and (iii) ring contraction of [1,2,4]triazolo[3,4- b ][1,3,4]thiadiazines. , …”

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confidence: 99%

Cu(I)-Catalyzed Regioselective Synthesis of Pyrazolo[5,1-c]-1,2,4-triazoles

et al. 2012

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Electrochemical investigations of some newly synthesized arylazapyrazole derivatives

et al. 2016

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Three derivatives of arylazapyrazole ((E)-4-(phenyldiazenyl)-3,5-dimethyl-1H-pyrazole, (E)-4-[(4-fluorophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole, and (E)-4-[(4-iodophenyl)diazenyl]-3,5-dimethyl-1H-pyrazole) were synthesized, characterized, and further investigated for their electrochemical behavior at glassy carbon electrode using cyclic voltammetry. All compounds were reduced following E i C i mechanism giving single cathodic peak in potential range 0 to -2 V vs. Ag/AgCl. The plots of log i P vs. log m showed that the electrode process is mixed adsorption-diffusion controlled. The kinetic parameters such as transfer coefficient (an), diffusion coefficients (D o ), and standard heterogeneous rate constants (k s ) were determined from the electrochemical data. The values of D o were determined and found greater for the smallest among the three compounds. k s values were calculated by Laviron formalism which lies in the order of 10 -2 s -1 . Temperature and pH effects were studied and thermodynamic parameters such as change in free energy of activation (DG # ), apparent activation energy (E a ), enthalpy (DH # ), and entropy (DS # ) of activation were determined. Negative values of E a , DH # , and DS # imply that the electrode process needs lesser over potential with temperature rise, pre-adsorption of the analyte onto the electrode surface and the activated complex has a more organized structure than the reactants, respectively. Graphical abstract

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Synthesis and Electrochemical Behavior of Some 1H-3-Methyl-4-ethoxycarbonyl-5-(benzylidenehydrazino)pyrazoles

Cited by 9 publications

References 7 publications

Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure–Activity Relationships of the Novel PPP4pT Series

Steric Blockade of Oxy-Myoglobin Oxidation by Thiosemicarbazones: Structure–Activity Relationships of the Novel PPP4pT Series

Cu(I)-Catalyzed Regioselective Synthesis of Pyrazolo[5,1-c]-1,2,4-triazoles

Electrochemical investigations of some newly synthesized arylazapyrazole derivatives

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