Electrochemical aspects of the reduction of biologically active 2-hydroxy-3-alkyl-1,4-naphthoquinones

被引:86
作者
Ferraz, PAL
de Abreu, FC
Pinto, AV
Glezer, V
Tonholo, J
Goulart, MOF
机构
[1] Univ Fed Alagoas, CCEN, Dept Quim, BR-57072970 Maceio, Alagoas, Brazil
[2] Univ Fed Pernambuco, Dept Quim Fundamental, Recife, PE, Brazil
[3] UFRJ, Rio De Janeiro, Brazil
[4] Hebrew Univ Jerusalem, Environm Chem Lab, Jerusalem, Israel
来源
JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 2001年 / 507卷 / 1-2期
关键词
2-hydroxy-3-allylnaphthoquinones; lapachol; cyclic voltammetry; electrolysis; proton effects; self-protonation;
D O I
10.1016/S0022-0728(01)00439-9
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
A series of natural and synthetic 2-hydroxy-3-alkylnaphthoquinones, several of them with relevant biological activities, showed typical voltammograms, on Hg and glassy carbon electrodes, in aprotic medium (DMF-0.1 mol l(-1) TBAP). Two main pairs of peaks, the first one corresponding to irreversible and the second one to quasi-reversible processes, were observed. Intermediate shoulders were also present. They showed strong dependence on scan rate, concentration and pK(a) of added proton sources. Lapachol was chosen for detailed investigations, on Hg and glassy carbon electrodes. A self-protonation mechanism and hydrogen-bonded intermediates explain the nature of the first peaks and shoulders. The last pair of peaks is related to the quasi-reversible two-electronic reduction of the respective anion of the 2-hydroxynaphthoquinones (NQOH). Addition of proton sources of different strength caused pK(a)-dependent modifications of voltammograms. Electrochemical effects are demonstrated over the full reduction range, from protonation of unreduced quinones to hydrogen-bonding of reduced dianions. Strong acids like trifluoroacetic acid cause protonation of the original quinone and consequent easier reduction. Benzoic acid is strong enough to cause the merging of the waves into one pair of irreversible waves. Phenol is able to modify only the more basic electrogenerated intermediates. Some OH-free derivatives were prepared and their voltammetric behavior observed. They showed the expected quinone reduction pattern. (C) 2001 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:275 / 286
页数:12
相关论文
共 35 条
[1]   KINETICS AND MECHANISM OF SELF-PROTONATION REACTIONS IN ORGANIC ELECTROCHEMICAL PROCESSES [J].
AMATORE, C ;
CAPOBIANCO, G ;
FARNIA, G ;
SANDONA, G ;
SAVEANT, JM ;
SEVERIN, MG ;
VIANELLO, E .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1985, 107 (07) :1815-1824
[2]  
[Anonymous], CHEM QUINONOID COMPO
[3]  
ASHNAGAR A, 1984, BIOCHIM BIOPHYS ACTA, V801, P351, DOI 10.1016/0304-4165(84)90138-7
[4]   ELECTRON TRANSFER TO AROMATIC HYDROCARBONS AT THE DROPPING MERCURY ELECTRODE [J].
ATEN, AC ;
BUTHKER, C ;
HOIJTINK, GJ .
TRANSACTIONS OF THE FARADAY SOCIETY, 1959, 55 (02) :324-330
[5]  
BEZUGLYI VD, 1976, J GEN CHEM USSR, V46, P693
[6]   VOLTAMMETRIC AND SPECTROSCOPIC STUDY OF THE IRON(II) COMPLEXES WITH THE SEMIQUINONE OF 2-HYDROXY-1,4-NAPHTHOQUINONE (LAWSONE) IN APROTIC MEDIUM [J].
BODINI, ME ;
BRAVO, PE ;
ARANCIBIA, V .
POLYHEDRON, 1994, 13 (03) :497-503
[7]   MANGANESE COMPLEXES WITH 2-HYDROXY-3(3-METHYL-2-BUTENYL)-1,4-NAPHTHOQUINONE (LAPACHOL) - REDOX CHEMISTRY AND SPECTROSCOPY IN DIMETHYLSULFOXIDE [J].
BODINI, ME ;
ARANCIBIA, V .
POLYHEDRON, 1989, 8 (11) :1407-1412
[8]   Influence of endothelin ETA and ETB receptor antagonists on endothelin-induced contractions of the guinea pig isolated gall bladder [J].
Cardozo, AM ;
DOrleansJuste, P ;
Yano, M ;
Frank, PA ;
Rae, GA .
REGULATORY PEPTIDES, 1997, 69 (01) :15-23
[9]   The electrochemistry of antineoplastic furanquinones: Electrochemical properties of benzo[b]naphtho[2,3-d]furan-6,11-dione derivatives [J].
Crawford, PW ;
Carlos, E ;
Ellegood, JC ;
Cheng, CC ;
Dong, Q ;
Liu, DF ;
Luo, YL .
ELECTROCHIMICA ACTA, 1996, 41 (15) :2399-2403