Polarographie der Harnstoff- und Thioharnstoffderivate XI. Bemerkungen zur Polarographie einiger Mercaptopurine

Horn, G.; Zuman, P.

doi:10.1135/cccc19603401

Cited by 20 publications

(6 citation statements)

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“…It was found, by ultraviolet spectrophotometric studies that 1 mole of PDS rapidly decomposed to give approximately 1.5 mole of 6-TP; no other easily observable spectrophotometric absorption peaks were observed. Polarograms of PDS in ammonia solution pH 9 after 6 hr at room temperature were qualitatively identical to those observed after complete electrolysis of 6-TP at wave II in the same background, except that the anodic wave of 6-TP was also observed, Ez/2 ~ --0.40V (23). Earlier workers have shown that PDS decomposes in alkaline solution to give 75% of 6-TP and 25% of the appropriate salt of purine-6-sulfinic acid (P-6-Si) (12).…”

Section: Macroscale Electrozysissupporting

confidence: 65%

“…Polarograms of PDS in ammonia solution pH 9 after 6 hr at room temperature were qualitatively identical to those observed after complete electrolysis of 6-TP at wave II in the same background, except that the anodic wave of 6-TP was also observed, Ez/2 ~ --0.40V (23). Accordingly, the stability of authentic PDS in ammonia pH 9.1 was examined.…”

Section: Oxidation Of 6-thiopurinesupporting

confidence: 54%

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Electrochemical Oxidation of 6-Thiopurine at the Pyrolytic Graphite Electrode

Dryhurst¹

1969

J. Electrochem. Soc.

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The electrochemical oxidation of 6-thiopurine (6-TP), which gives three well defined voltammetric waves at the pyrolytic graphite electrode (PGE), has been investigated by linear sweep and cyclic voltammetry, macroscale controlled electrode potential electrolysis at the PGE in aqueous 1M acetic acid (pH 2.3), ammonia buffer pH 9 and carbonate buffer pH 9, and by determination of reaction products and possible intermediates. The electrochemical oxidation of 6-TP appears to follow a pathway quite different from the major enzymatic oxidative route. The first pH dependent wave is an adsorption wave due to oxidation of 6-TP to give an adsorbed layer of product bis (6-purinyl) disulfide (PDS). The second pH-dependent wave is ale process to give PDS both at pH 2.3 and pH 9; however at pH 2.3 further slow chemical oxidation to a disulfone or disulfoxide occurs, while in ammonia pH 9 the PDS decomposes rapidly to 6-TP, purine-6-sulfinic acid (P-6-Si) and purine-6sulfonamide (P-6-Sm), with possibly some purine-6-sulfonic acid (P-6-So), with the over-all result that somewhat in excess of 4e are transferred. The third pH dependent wave in carbonate pH 9 gives P-6-So as the final product; in ammonia pH 9 wave III gives rise to a mixture of P-6-Si, P-6-Sm and possibly some P-6-So; PDS appears to be an unstable intermediate in these oxidations at high pH capable of being chemically oxidized by dissolved atmospheric oxygen. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-10 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.217.58.200 Downloaded on 2015-04-10 to IP

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Section: Macroscale Electrozysissupporting

confidence: 65%

Section: Oxidation Of 6-thiopurinesupporting

confidence: 54%

Electrochemical Oxidation of 6-Thiopurine at the Pyrolytic Graphite Electrode

Dryhurst¹

1969

J. Electrochem. Soc.

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“…Discussion of such processes with a colleague from a Research Institute for Pharmacy and Biochemistry (J. JıB lek) resulted in a gift of a series of thiobarbiturates. Polarographic investigation of thiobarbiturates (17)(18)(19)(20)(21)(22)(23) was later extended to further derivatives of urea and thiourea (24) (such as thiohydantoins and thiopyrimidines (25,26), uracils and thiouracils (27,28)) as well as thioimidazoles (29,30), mercaptobenzthiazoles and mercaptobenzimidazoles (31), simple thiols, including glutathione (32), 1,2-dithiols (33-37), dithiocarbamates (38)(39)(40)(41)(42)(43), and mercaptopurines (44). All these experiments were carried out in the hope that the structural effects would make it possible to elucidate details of electrode processes involved.…”

Section: Anodic Waves Of Organic Species Corresponding To Formation Omentioning

confidence: 99%

Half a Century of Research Using Polarography

Zuman

1997

Microchemical Journal

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“…With increasing alcohol concentration in the solution, the four-electron reduction wave decreases to a one-electron wave (reduction into anion radicals) and at more negative potentials, a new wave appears and begins to grow, corresponding to the reduction of the unprotonated anion radicals of 2-nitrofuran [870]. A great number of similar examples can be cited (see [843,851,860,674,[871][872][873]). …”

Section: Electrode Processes With Antecedent Protonationmentioning

confidence: 99%

Catalytic and Kinetic Waves in Polarography

Mairanovskii¹

1968

129

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Polarographie der Harnstoff- und Thioharnstoffderivate XI. Bemerkungen zur Polarographie einiger Mercaptopurine

Cited by 20 publications

References 0 publications

Electrochemical Oxidation of 6-Thiopurine at the Pyrolytic Graphite Electrode

Electrochemical Oxidation of 6-Thiopurine at the Pyrolytic Graphite Electrode

Half a Century of Research Using Polarography

Catalytic and Kinetic Waves in Polarography

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