%0 Journal Article
%T Synthesis and Conformational Assignment of N-(E)-Stilbenyloxymethylenecarbonyl-Substituted Hydrazones of Acetone and o -( m - and p -) Chloro- (nitro-) benzaldehydes by Means of and NMR Spectroscopy
%A Przemysˋaw Patorski
%A Elˋbieta Wyrzykiewicz
%A Graˋyna Bartkowiak
%J Journal of Spectroscopy
%D 2013
%R 10.1155/2013/197475
%X Eighteen new N-(E)-stilbenyloxyalkylcarbonyl-substituted hydrazones of ortho- (meta- and para-) chloro- (nitro-) benzaldehydes 1每18 and two analogous hydrazones of acetone 19-20 were prepared. The stereochemical behavior of 1每18 in dimethyl-d6 sulfoxide solution has been studied by NMR and NMR techniques, using spectral data of 19 and 20 as supporting material. The E-geometrical isomers and cis-/trans-amide conformers have been found for these hydrazones. Energy barriers of isomers are reported. 1. Introduction The N-substituted hydrazones of aldehydes are of interest because of their biological and pharmacological activities [1每5], as well as considerable chelating power with transition metals [6每9]. They can be used in analytical chemistry to cover and analyze metals selectively as hydrazone complexes. Hydrazones of o-(m- and p-) chlorobenzaldehydes and o-(m- and p-) nitrobenzaldehydes have been reported in the literature [10每13]. Chloro- and nitrobenzaldehydes are widely used as reagents for organic synthesis, chiefly as reactants for manufacturing pharmaceuticals, plastic additives, pesticides, dyes and metal finishing agents. For example, 2-chlorobenzaldehyde is an intermediate for the optical brighteners production and finds its application as the brightening agent for zinc plating, whereas 2-nitrobenzaldehyde is a substrate for indigo synthesis in the Baeyer-Drewson method [14] and easy removable protection group for many functionalities [15]. However, despite the many synthetic applications of substituted benzaldehydes, to the best of our knowledge no work has been published in the literature about the synthesis and physicochemical properties of N-(E)-stilbenyloxyalkylcarbonyl substituted hydrazones of ortho- (meta- and para-) chloro- and (nitro-) benzaldehydes. These compounds, containing amide and hydrazone functions in their molecules, seemed to be suitable candidates for further chemical modifications and may be pharmacologically active and analytically useful. It ought to be pointed out that (E)-stilbenes hydroxylated at one to five positions as well as their ethereal derivatives are produced by woody plants and exhibit a broad spectrum of biological activity [16每20]. We have previously reported the synthesis, physicochemical properties, as well as mass spectrometric study of N-(E)-stilbenyloxyalkylcarbonyl substituted hydrazones of o-(m- and p-) hydroxybenzaldehydes and 2-(3- and 4-)pyridinecarboxyaldehydes [21每26]. Our studies have been recently extended to N-(E)-stilbenyloxymethylenecarbonyl substituted hydrazones of o-(m- and p-)
%U http://www.hindawi.com/journals/jspec/2013/197475/