Nucleic acids are electroactive species producing well developed voltammetric peaks on the mercury electrode sensitively reflecting small damages to the double-helical DNA. Nucleic acid-modified electrodes can easily be prepared by immersing the electrode into a 5 μL drop of the DNA and/or RNA solution. Such nucleic acid-modified electrodes strongly decrease the quantities of DNA and RNA required for analysis. They offer a number of other advantages which may be of use in biochemical and molecular biological research. Past, present and future aspects of nucleic acid voltammetric analysis are reviewed.

From polarography of DNA to microanalysis with nucleic acid-modified electrodes

Sigma- and Pi-Electron Delocalization: Focus on Substituent Effects

A simplified procedure for the stereospecific transformation of 1,2-diols into epoxides

The practical usefulness of a correlation equation as well as its significance in theory strongly depend on its range of validity, not only as it is defined but also as its use is restricted in practice by the number of parameters actually known. Hence the tables of parameters are of primary importance and reflect the actual state of a given field. In this chapter attention is focused on constants characterizing the substituent, which are mainly denoted by the letter σ with various subscripts and superscripts, but sometimes also by other symbols (E s, v). The correlation equation most frequently has the form (10.1). For the most common equations of this type 

$$y = \rho _0 + \sum\limits_{i = 1}^A {\rho _i \sigma _i } $$

(10.1)

(Hammett, Taft, Yukawa-Tsuno) many tabulations of σ constants are available (e.g. Refs. 1–13), but authors usually select from the literature only one preferred value for each substituent and the extent of the table is always a compromise between two demands: reliability and completeness. Actually neither can be fully satisfied, so that the user cannot really rely on all the data on the one hand, and must always search for additional data on the other. The problem is more urgent than with the tabulation of any other constants, since the individual σ values are not only of varying precision but may even be defined and calculated in quite different ways. It follows that the main problem of this chapter will be the clear definition of how a given σ value was obtained.

A Critical Compilation of Substituent Constants

Der Effekt der sogenannten „through-bond”-Wechselwirkung wird exemplarisch an 1,4-Butandiyl abgeleitet, und daraus resultierende Anderungen fur den Grundzustand des Systems werden aufgezeigt. Spektroskopische Nachweise dieses Effekts sollen diskutiert, seine chemischen Konsequenzen an verschiedenen Beispielen ausgelotet werden.

„Through‐bond”︁‐Wechselwirkungseffekte

Azabicyclo compounds. XII. 4-Substituted quinuclidines as model compounds for the study of polar effects transfer

Obtention d'aryl-3 oxirannecarbonitriles et d'aryl-3 methyl-3 oxirannecarbonitriles qui sont hydrolyses en esters methyliques

Reaction of 4-substituted benzaldehydes and acetophenones with chloroacetonitrile

[1]Benzothieno[3,2- b ]furan reacts with substituted dienes 2 as a dienophile under formation of substituted tetrahydro[1]benzothieno[3,2- b ][1]benzofuran derivatives 3-14 . The cycloaddition is endo -stereoselective. Aromatization of the products leads to a series of new fused [1]benzothieno[3,2- b ][1]benzofurans 17-24 . The 1 H NMR spectra of the new compounds were fully assigned.

Diels-Alder Reactions of [1]Benzothieno[3,2-b]furan

A new heterocyclic compound has been prepared by four step synthesis. The reaction of methyl thiosalicylate I with excess methyl chloroacetate in the presence of potassium carbonate gives methyl 3-[(methoxycarbonyl)methoxy]benzo[ b ]thiofen-2-carboxylate ( II ) which on cyclization by action of potassium tert -butoxide gives methyl 3-hydroxy[1]benzothieno[3,2- b ]furan-2-carboxylate ( III ). Its base catalyzed hydrolysis and decarboxylation forms [1]benzothieno[3,2- b ]furan-3(2 H )-one ( IV ) whose reduction with NaBH 4 gives the title compound.

Jaroslav Paleček

Papers

Azabicyclo compounds. XII. 4-Substituted quinuclidines as model compounds for the study of polar effects transfer

Reaction of 4-substituted benzaldehydes and acetophenones with chloroacetonitrile

Diels-Alder Reactions of [1]Benzothieno[3,2-b]furan

Synthesis of [1]Benzothieno[3,2-b]furan - A New Fused Benzoheterocyclic System

On dihydropyridines. XX. Reactions of organomagnesium and organolithium reagents with 3,5-dicyano-2,6-dimethylpyridine