%0 Journal Article %1 Baraldi2000 %A Baraldi, P. G. %A Cacciari, B. %A Romagnoli, R. %A Spalluto, G. %A Moro, S. %A Klotz, K. N. %A Leung, E. %A Varani, K. %A Gessi, S. %A Merighi, S. %A Borea, P. A. %D 2000 %J J Med Chem %K AMP/biosynthesis Adenosine Animals Assay CHO Cricetinae Cyclic Humans Models, Molecular P1/*antagonists Purinergic Pyrazoles/*chemistry Pyrimidines/*chemical Radioligand Relationship Structure Structure-Activity inhibitors synthesis/chemistry/pharmacology Receptor Cell %N 25 %P 4768-80 %T Pyrazolo4,3-e1,2,4-triazolo1,5-cpyrimidine derivatives as highly potent and selective human A(3) adenosine receptor antagonists: influence of the chain at the N(8) pyrazole nitrogen %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11123985 %V 43 %X An enlarged series of pyrazolotriazolopyrimidines previously reported, in preliminary form (Baraldi et al. J. Med. Chem. 1999, 42, 4473-4478), as highly potent and selective human A(3) adenosine receptor antagonists is described. The synthesized compounds showed A(3) adenosine receptor affinity in the sub-nanomolar range and high levels of selectivity evaluated in radioligand binding assays at human A(1), A(2A), A(2B), and A(3) adenosine receptors. In particular, the effect of the chain at the N(8) pyrazole nitrogen was analyzed. This study allowed us to identify the derivative with the methyl group at the N(8) pyrazole combined with the 4-methoxyphenylcarbamoyl moiety at the N(5) position as the compound with the best binding profile in terms of both affinity and selectivity (hA(3) = 0.2 nM, hA(1)/hA(3) = 5485, hA(2A)/hA(3) = 6950, hA(2B)/hA(3) = 1305). All the 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. The new compounds are among the most potent and selective A(3) antagonists so far described. The derivatives with higher affinity at human A(3) adenosine receptors proved to be antagonists, in the cAMP assay, capable of inhibiting the effect of IB-MECA with IC(50) values in the nanomolar range, with a trend strictly similar to that observed in the binding assay. Also a molecular modeling study was carried out, with the aim to identify possible pharmacophore maps. In fact, a sterically controlled structure-activity relationship was found for the N(8) pyrazole substituted derivatives, showing a correlation between the calculated molecular volume of pyrazolo4,3-e1,2, 4-triazolo1,5-cpyrimidine derivatives and their experimental K(i) values.

@article{Baraldi2000, abstract = {An enlarged series of pyrazolotriazolopyrimidines previously reported, in preliminary form (Baraldi et al. J. Med. Chem. 1999, 42, 4473-4478), as highly potent and selective human A(3) adenosine receptor antagonists is described. The synthesized compounds showed A(3) adenosine receptor affinity in the sub-nanomolar range and high levels of selectivity evaluated in radioligand binding assays at human A(1), A(2A), A(2B), and A(3) adenosine receptors. In particular, the effect of the chain at the N(8) pyrazole nitrogen was analyzed. This study allowed us to identify the derivative with the methyl group at the N(8) pyrazole combined with the 4-methoxyphenylcarbamoyl moiety at the N(5) position as the compound with the best binding profile in terms of both affinity and selectivity (hA(3) = 0.2 nM, hA(1)/hA(3) = 5485, hA(2A)/hA(3) = 6950, hA(2B)/hA(3) = 1305). All the 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. The new compounds are among the most potent and selective A(3) antagonists so far described. The derivatives with higher affinity at human A(3) adenosine receptors proved to be antagonists, in the cAMP assay, capable of inhibiting the effect of IB-MECA with IC(50) values in the nanomolar range, with a trend strictly similar to that observed in the binding assay. Also a molecular modeling study was carried out, with the aim to identify possible pharmacophore maps. In fact, a sterically controlled structure-activity relationship was found for the N(8) pyrazole substituted derivatives, showing a correlation between the calculated molecular volume of pyrazolo[4,3-e]1,2, 4-triazolo[1,5-c]pyrimidine derivatives and their experimental K(i) values.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Baraldi, P. G. and Cacciari, B. and Romagnoli, R. and Spalluto, G. and Moro, S. and Klotz, K. N. and Leung, E. and Varani, K. and Gessi, S. and Merighi, S. and Borea, P. A.}, biburl = {https://www.bibsonomy.org/bibtex/2a87d441c6240e9ee951dc5e6dc7c5dc7/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {4107acfecb07db049af20cce7eb767fe}, intrahash = {a87d441c6240e9ee951dc5e6dc7c5dc7}, 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 Purinergic Pyrazoles/*chemistry Pyrimidines/*chemical Radioligand Relationship Structure Structure-Activity inhibitors synthesis/chemistry/pharmacology Receptor Cell}, month = {Dec 14}, note = {Baraldi, P G Cacciari, B Romagnoli, R Spalluto, G Moro, S Klotz, K N Leung, E Varani, K Gessi, S Merighi, S Borea, P A Research Support, Non-U.S. Gov't United states Journal of medicinal chemistry J Med Chem. 2000 Dec 14;43(25):4768-80.}, number = 25, pages = {4768-80}, shorttitle = {Pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine derivatives as highly potent and selective human A(3) adenosine receptor antagonists: influence of the chain at the N(8) pyrazole nitrogen}, timestamp = {2010-12-14T18:20:38.000+0100}, title = {Pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine derivatives as highly potent and selective human A(3) adenosine receptor antagonists: influence of the chain at the N(8) pyrazole nitrogen}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11123985}, volume = 43, year = 2000 }