131304-34-2Relevant academic research and scientific papers
Aza-analogs of 8-styrylxanthines as A(2A)-adenosine receptor antagonists
Mueller, Christa E.,Sauer, Roland,Geis, Uli,Frobenius, Wolfram,Talik, Przemyslaw,Pawlowski, Muciej
, p. 181 - 189 (2007/10/03)
In the present study we synthesized aza-analogs of 8-styrylxanthines, in which the ethenyl bridge is replaced by an imine, amide, or azo function, in order to investigate structure-activity relationships of the 8-substituent of A(2A)-selective xanthine derivatives. Thus, various 8-substituents were combined with theophylline or caffeine, respectively, and affinities of the novel compounds for adenosine A1- and A(2A)-receptors were determined and compared with those of analogous 8-styrylxanthine derivatives. 8-(Benzylideneamino)caffeine derivatives exhibited high affinity and selectivity for A(2A)-adenosine receptors, but were unstable in aqueous buffer solution at physiological pH values. 8-(Phenylazo)caffeine derivatives were less potent than corresponding 8-styrylcaffeine derivatives at adenosine receptors. The most potent azo compound of the present series was 8-(m-chlorophenylazo)caffeine (14b) exhibiting a K(i) value of 400 nM at A(2A)-adenosine receptors and 20-fold selectivity versus A1-receptors. Due to the facile synthetic access to 8-(phenylazo)xanthine derivatives, which are obtained by coupling of 8-unsubstituted xanthines with phenyldiazonium salts, 14b may be an interesting new lead compound for the development of more potent and selective A(2A)-antagonists with azo structure.
POLAROGRAPHIC BEHAVIOUR OF SOME ARYLAZOTHEOPHYLLINES
Ismail, Mohamed I.,Iskander, Madlene L.
, p. 1978 - 1988 (2007/10/02)
The polarographic behaviour of a series of arylazotheophyllines was studied in aqueous alcoholic buffered media and in a DMF-0.1 m LiClO4 solution.The redox study gave evidence that the azo group is electroactive in aqueous as well as non-aqueous media.A mechanism interpreting the electrode process is proposed and confirmed through the identification of the controlled potential electrolysis products, the use of a model compound and the application of Hammett's ?-E relationship.The physico-chemical characteristics of these compounds, viz. the diffusion coefficient, dissociation constant, ionization potential and electron affinity, are also included.
