%0 Journal Article %1 Baraldi2002 %A Baraldi, P. G. %A Cacciari, B. %A Moro, S. %A Spalluto, G. %A Pastorin, G. %A Ros, T. Da %A Klotz, K. N. %A Varani, K. %A Gessi, S. %A Borea, P. A. %D 2002 %J J Med Chem %K AMP/biosynthesis Adenosine Animals Assay CHO Cricetinae Cyclic Humans Models, Molecular P1/*antagonists Protein Purinergic Pyrimidines/*chemical Radioligand Relationship Secondary Structure, Structure-Activity Transfection inhibitors/metabolism synthesis/chemistry/pharmacology Receptor Cell %N 4 %P 770-80 %T Synthesis, biological activity, and molecular modeling investigation of new pyrazolo4,3-e-1,2,4-triazolo1,5-cpyrimidine derivatives as human A(3) adenosine receptor antagonists %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11831890 %V 45 %X A new series of pyrazolotriazolopyrimidines bearing different substitutions on the phenylcarbamoyl moieties at the N5 position, being highly potent and selective human A(3) adenosine receptor antagonists, is described. The compounds represent an extension and an improvement of our previous work on this class of compounds (J. Med. Chem. 1999, 42, 4473-4478; J. Med. Chem. 2000, 43, 4768-4780). All the synthesized compounds showed A(3) adenosine receptor affinity in the subnanomolar range and high levels of selectivity in radioligand binding assays at the human A(1), A(2A), A(2B), and A(3) adenosine receptors. In particular, the effect of the substitution and its position on the phenyl ring have been studied. From binding data, it is evident that the unsubstituted derivatives on the phenyl ring (e.g., compound 59, hA(3) = 0.16 nM, hA(1)/hA(3) = 3713, hA(2A)/hA(3) = 2381, hA(2B)/hA(3) = 1388) showed the best profile in terms of affinity and selectivity at the human A(3) adenosine receptors. The introduction of a sulfonic acid moiety at the para position on the phenyl ring was attempted in order to design water soluble derivatives. However, this substitution led to a dramatic decrease of affinity at all four adenosine receptor subtypes. A computer-generated model of the human A(3) receptor was built and analyzed to better interpret these results, demonstrating that steric control, in particular at the para position on the phenyl ring, plays a fundamental role in the receptor interaction. Some of the synthesized compounds proved to be full antagonists in a specific functional model, where the inhibition of cAMP-generation by IB-MECA was measured in membranes of CHO cells stably transfected with the human A(3) receptor with IC(50) values in the nanomolar range, with a statistically significative linear relationship with the binding data.

@article{Baraldi2002, abstract = {A new series of pyrazolotriazolopyrimidines bearing different substitutions on the phenylcarbamoyl moieties at the N5 position, being highly potent and selective human A(3) adenosine receptor antagonists, is described. The compounds represent an extension and an improvement of our previous work on this class of compounds (J. Med. Chem. 1999, 42, 4473-4478; J. Med. Chem. 2000, 43, 4768-4780). All the synthesized compounds showed A(3) adenosine receptor affinity in the subnanomolar range and high levels of selectivity in radioligand binding assays at the human A(1), A(2A), A(2B), and A(3) adenosine receptors. In particular, the effect of the substitution and its position on the phenyl ring have been studied. From binding data, it is evident that the unsubstituted derivatives on the phenyl ring (e.g., compound 59, hA(3) = 0.16 nM, hA(1)/hA(3) = 3713, hA(2A)/hA(3) = 2381, hA(2B)/hA(3) = 1388) showed the best profile in terms of affinity and selectivity at the human A(3) adenosine receptors. The introduction of a sulfonic acid moiety at the para position on the phenyl ring was attempted in order to design water soluble derivatives. However, this substitution led to a dramatic decrease of affinity at all four adenosine receptor subtypes. A computer-generated model of the human A(3) receptor was built and analyzed to better interpret these results, demonstrating that steric control, in particular at the para position on the phenyl ring, plays a fundamental role in the receptor interaction. Some of the synthesized compounds proved to be full antagonists in a specific functional model, where the inhibition of cAMP-generation by IB-MECA was measured in membranes of CHO cells stably transfected with the human A(3) receptor with IC(50) values in the nanomolar range, with a statistically significative linear relationship with the binding data.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Baraldi, P. G. and Cacciari, B. and Moro, S. and Spalluto, G. and Pastorin, G. and Ros, T. Da and Klotz, K. N. and Varani, K. and Gessi, S. and Borea, P. A.}, biburl = {https://www.bibsonomy.org/bibtex/24b47f7e4bcab062e833d512de0103cb5/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {ad78a5c7f6df17adb175a72cf2d71a99}, intrahash = {4b47f7e4bcab062e833d512de0103cb5}, issn = {0022-2623 (Print) 0022-2623 (Linking)}, journal = {J Med Chem}, keywords = {AMP/biosynthesis Adenosine Animals Assay CHO Cricetinae Cyclic Humans Models, Molecular P1/*antagonists Protein Purinergic Pyrimidines/*chemical Radioligand Relationship Secondary Structure, Structure-Activity Transfection inhibitors/metabolism synthesis/chemistry/pharmacology Receptor Cell}, month = {Feb 14}, note = {Baraldi, Pier Giovanni Cacciari, Barbara Moro, Stefano Spalluto, Giampiero Pastorin, Giorgia Da Ros, Tatiana Klotz, Karl-Norbert Varani, Katia Gessi, Stefania Borea, Pier Andrea Research Support, Non-U.S. Gov't United States Journal of medicinal chemistry J Med Chem. 2002 Feb 14;45(4):770-80.}, number = 4, pages = {770-80}, shorttitle = {Synthesis, biological activity, and molecular modeling investigation of new pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine derivatives as human A(3) adenosine receptor antagonists}, timestamp = {2010-12-14T18:20:38.000+0100}, title = {Synthesis, biological activity, and molecular modeling investigation of new pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine derivatives as human A(3) adenosine receptor antagonists}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11831890}, volume = 45, year = 2002 }