- Design, synthesis and molecular docking study of new purine derivatives as Aurora kinase inhibitors
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Nine new purine-based compounds were designed and have been synthesized through series reactions of the starting compound 8-amino-substituted purine (2) with various reagents. Full characterizations of the synthesized compounds were performed to elucidate
- Khalifa, Mohamed E.
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- Purines. part XVI
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A series of N-substituted 8-aminoxanthines (=8-amino-3,7(or 3,9)-dihydro-1H-purine-2,6-diones) 8-16 and 34-37 were synthesized from the corresponding 8-nitroxanthines 1-7, 30-33, and 8-(phenylazo)xanthines 17 and 18 by catalytic reduction. Another approac
- Mosselhi, Mosselhi A.,Pfleiderer, Wolfgang
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experimental part
p. 2115 - 2134
(2011/02/17)
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- Pteridines. Part CXIX: A new pteridine - Purine transformation
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A variety of pyrimidine precursors 12-25 were converted into a series of new 7-hydroxylumazines (=7-hydroxypteridine-2,4(1H,3H)-diones) 26-35 which functioned as starting materials for the transformation into the corresponding 7-chlorolumazines 36-45. Subsequent reaction with hydrazine led to the 7-hydrazinolumazines 46-55 which gave on nitrosation the 7-azidolumazines 1 and 56-64. These compounds were subjected to short heating in xylene whereby 1 and 56-61 showed a new pteridine-purine interconversion in forming a new type of 1,3-disubstituted or 3-substituted xanthin-8-amine-derived nitrilium ylides (2,3,6,7-tetrahydro-N-methylidyne-2,6-dioxo-1H-purin-8-aminium ylides) 11 and 65-70. The presence of an additional 6-alkyl substituent in the 7-azidolumazines 63 and 64 or of an unsubstituted N(3) position in 62 caused further rearrangement to xanthine-9-carbonitriles 71-73. Prolonged heating of 7-azido-1,3-dimethyllumazine (1) also afforded theophylline-9-carbonitrile (=1,2,3,6-tetrahydro-1,3-dimethyl-2,6-dioxo-9H-purine-9-carbonitrile; 5). The nitrilium ylide function was established by NMR and UV spectra as well as by elemental analyses. Confirmation of the nitrilium ylide structures was suggested by the result of the heating of 1,3-dimethyl-N-methylidynexanthin-8-aminium ylide 11 in EtOH or of 1 in pentan-1-ol leading to 8-aminotheophylline (=8-amino-3,7-dihydro-1,3-dimethyl-1H-purin-2,6-dione; 74).
- Pfleiderer, Wolfgang
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experimental part
p. 338 - 353
(2009/02/07)
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- Structure-activity relationship studies of a new series of imidazo[2,1-f]purinones as potent and selective A3 adenosine receptor antagonists
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We recently described the synthesis of 1-benzyl-3-propyl-1H,8H-imidazo[2,1-f]purine-2,4-diones, new potent and selective A3 adenosine receptor antagonists containing a xanthine core. The present work can be considered an extension of our SAR st
- Baraldi, Pier Giovanni,Preti, Delia,Tabrizi, Mojgan Aghazadeh,Romagnoli, Romeo,Saponaro, Giulia,Baraldi, Stefania,Botta, Maurizio,Bernardini, Cesare,Tafi, Andrea,Tuccinardi, Tiziano,Martinelli, Adriano,Varani, Katia,Borea, Pier Andrea
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experimental part
p. 10281 - 10294
(2009/04/06)
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- Aza-analogs of 8-styrylxanthines as A(2A)-adenosine receptor antagonists
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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.
- Mueller, Christa E.,Sauer, Roland,Geis, Uli,Frobenius, Wolfram,Talik, Przemyslaw,Pawlowski, Muciej
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p. 181 - 189
(2007/10/03)
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- POLAROGRAPHIC BEHAVIOUR OF SOME ARYLAZOTHEOPHYLLINES
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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.
- Ismail, Mohamed I.,Iskander, Madlene L.
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p. 1978 - 1988
(2007/10/02)
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- DIRECT THIOLATION OF N-BENZYLIDENEAMINOAZOLES. NEW METHOD FOR THE SYNTHESIS OF N-AMINO-1,2,4-TRIAZOLINETHIONES AND N-AMINOBENZIMIDAZOLINE-2-THIONES
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When heated with sulfur, the N-benzylideneamino derivatives of benzimidazole and 1,2,4-triazole give good or moderate yields of N-benzylideneaminobenzimidazoline-2-thiones and N-benzylideneamino-1,2,4-triazolinethiones, which are hydrolyzed smoothly in an
- Kuz'menko, V.V.,Pozharskii, A.F.,Kuz'menko, T.A.,Kryshtalyuk, O.V.
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p. 1577 - 1581
(2007/10/02)
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- SYNTHESIS AND PROPERTIES OF UNUSUALLY STABLE, HETEROCYCLIC NITRILIUM-YLIDES
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7-Azido-1,3-disubstituted lumazines show at elevated temperatures two new ring contractions leading to 9-cyanoxathines and a new type of stable purin-8-yl nitrilium ylides.This high stability is due to a strong resonance stabilization of the negatively charged purinyl anion moiety, which does not even afford a bulky substituent at the nitrilium C-atom to counteract secondary reactions.The structures of the new nitrilium ylides have been proven by spectral means and comparisons with model substances.
- Pfleiderer, Wolfgang
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p. 203 - 208
(2007/10/02)
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- N-DEBENZYLATION REACTION OF 8-BENZYLAMINOXANTHINES. PART I. SYNTHESIS OF 8-AMINOTHEOPHYLLINE AND SOME OF ITS DERIVATIVES
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Acid-catalyzed debenzylation reaction of 8-benzylaminotheophylline and some of its derivatives has been investigated.
- Pawlowski, Maciej,Gorczyca, Maria
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p. 837 - 841
(2007/10/02)
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