Elektro-Deblockierung — Elektrochemische Abspaltung von Schutzgruppen

Abstract

Viele Schutzgruppen lassen sich durch elektrochemische Reaktionen entfernen. In diesem Aufsatz werden theoretische und präparative Aspekte der Methode anhand von Beispielen diskutiert. Die Abspaltung erfordert oft hohe Potentiale. Durch Verwendung modifizierter Schutzgruppen („innere Aktivierung”︁) oder durch Zusatz von Katalysatoren (Elektronenüberträgern), die den Elektronenübergang entgegen dem Standardpotential‐Gradienten ermöglichen („äußere Aktivierung”︁), kann der Anwendungsbereich der elektrochemischen Methode erweitert werden.

Electrochemistry in a Divided World

“…The catalysts tungsten carbide (WC) [272][273][274] and carbon [275][276][277][278][279] for electrodes working in acidic electrolyte were studied in the topics of fuel cells.…”

“…This happened at the time of the so-called Doctor's plot, when medical doctors of Jewish origin were blamed of attempting the assassination of Soviet leaders. The most important results, which are still valid, from the period 1944 to 1961 concerned the mechanism of polarization of a Ni-anode during the oxygen evolution reaction involving the participation of Ni(III) and Ni(IV) oxides [277][278][279][280]. Parallel to these studies, in 1946 Tur'yan started to use more and more polarography to study chemical reactions.…”

“…Later, we propagate this technique to a great number of other groups [279,280]. In most cases, the process was carried out under рН control (Sect.…”

“…9.2.1, "Electrolysis at a Constant "pH" ("pX") with Recording Equipment"). The HOMEC is also efficient for labile substrates and for difficult reducible (oxydable) groups [279][280][281]. For example, the HOMEC's electron transfer beyond the supporting electrolyte discharge region was used to obtain glycine from its Z derivate with quantitative yield.…”

Alkylsulfanylphenyl Derivatives of Cytosine and 7‐Deazaadenine Nucleosides, Nucleotides and Nucleoside Triphosphates: Synthesis, Polymerase Incorporation to DNA and Electrochemical Study

“…Alkylsulfanyl groups, apart from being anchors for binding to metal surfaces, [5] are potentially interesting both as redox labels and as precursors of free thiols by chemical deprotection [12] or electroreduction. [13] The goals of our present study were the synthesis of nucleosides, nucleotides and dNTPs bearing either a free sulfanyl-or alkylsulfanylphenyl group attached directly to a nucleobase and the development of polymerase incorporations of the sulfur-containing dNTPs into DNA. Additionally, we studied the electrochemical behaviour of the modified nucleotides and DNA and their assembly onto the metal electrode surfaces.…”