Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives: Potent and Selective A2A Adenosine Antagonists
摘要:
A series of pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine derivatives (10a-o,q,r), bearing alkyl and aralkyl chains on positions 7 and 8, were synthesized in the attempt to obtain potent and selective antagonists for the A(2A) adenosine receptor subtype. The compounds were tested in binding and functional assays to evaluate their potency for the A(2A) compared with the A(1) adenosine receptor subtype. In binding studies in rat brain membranes, most of the compounds showed affinity for A(2A) receptors in the low nanomolar range with a different degree of A(2A) versus A(1) selectivity. Comparison of N-7 (10a-d,h-o)- and N-8 (10e-g)-substituted pyrazolo derivatives indicates that N-7 substitution decreases the A(1) affinity with the concomitant increase of A(2A) selectivity. Specifically, the introduction of a 3-phenylpropyl group at pyrazolo nitrogen in position 7 (101) increased significantly the A(2A) selectivity, being 210-fold, while the A(2A) receptor affinity remained high (K-i = 2.4 nM). With regards to the affinity for A(2A) receptors, also the compound 10n, bearing in the 7-position a beta-morpholin-4-ylethyl group, deserves attention (K-i = 5.6 nM) even though the A(2A) selectivity (84-fold) was not as high as that of 101. Conversely, the compound 10m (N-7-4-phenylbutyl derivative) showed a remarkable selectivity (A(1)/A(2A) ratio = 129) associated with lower A(2A) affinity (K-i = 21 nM). In functional studies, most of the compounds examined reversed 5'-(N-ethylcarbamoyl)adenosine-induced inhibition of rabbit platelet aggregation inhibition which is a biological response mediated by the A(2A) receptor subtype. The compounds are potent and selective A(2A) antagonists which can be useful to elucidate the pathophysiological role of this adenosine receptor subtype. These compounds deserve to be further developed to assess their potential for treatment of neurodegenerative disorders such as Parkinson's disease.
Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives: Potent and Selective A2A Adenosine Antagonists
摘要:
A series of pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine derivatives (10a-o,q,r), bearing alkyl and aralkyl chains on positions 7 and 8, were synthesized in the attempt to obtain potent and selective antagonists for the A(2A) adenosine receptor subtype. The compounds were tested in binding and functional assays to evaluate their potency for the A(2A) compared with the A(1) adenosine receptor subtype. In binding studies in rat brain membranes, most of the compounds showed affinity for A(2A) receptors in the low nanomolar range with a different degree of A(2A) versus A(1) selectivity. Comparison of N-7 (10a-d,h-o)- and N-8 (10e-g)-substituted pyrazolo derivatives indicates that N-7 substitution decreases the A(1) affinity with the concomitant increase of A(2A) selectivity. Specifically, the introduction of a 3-phenylpropyl group at pyrazolo nitrogen in position 7 (101) increased significantly the A(2A) selectivity, being 210-fold, while the A(2A) receptor affinity remained high (K-i = 2.4 nM). With regards to the affinity for A(2A) receptors, also the compound 10n, bearing in the 7-position a beta-morpholin-4-ylethyl group, deserves attention (K-i = 5.6 nM) even though the A(2A) selectivity (84-fold) was not as high as that of 101. Conversely, the compound 10m (N-7-4-phenylbutyl derivative) showed a remarkable selectivity (A(1)/A(2A) ratio = 129) associated with lower A(2A) affinity (K-i = 21 nM). In functional studies, most of the compounds examined reversed 5'-(N-ethylcarbamoyl)adenosine-induced inhibition of rabbit platelet aggregation inhibition which is a biological response mediated by the A(2A) receptor subtype. The compounds are potent and selective A(2A) antagonists which can be useful to elucidate the pathophysiological role of this adenosine receptor subtype. These compounds deserve to be further developed to assess their potential for treatment of neurodegenerative disorders such as Parkinson's disease.
Organoruthenium Antagonists of Human A<sub>3</sub>Adenosine Receptors
作者:Priyankar Paira、Mun Juinn Chow、Gopalakrishnan Venkatesan、Vamsi Krishna Kosaraju、Siew Lee Cheong、Karl-Norbert Klotz、Wee Han Ang、Giorgia Pastorin
DOI:10.1002/chem.201203291
日期:2013.6.17
triazolo moiety with an organoruthenium fragment. The objective was to introduce by design structural diversity into the PTP scaffold in order to tune their binding efficacy toward the target receptor. These novel organorutheniumantagonists displayed good aquatic stability and moderate binding affinity toward the hA3 receptor in the low micromolar range. The assembly of these complexes through a template‐driven
Antimicrobial and antitumor activity of n-heteroimmine-1,2,3-dithiazoles and their transformation in triazolo-, imidazo-, and pyrazolopirimidines
作者:Pier Giovanni Baraldi、Maria Giovanna Pavani、Maria del Carmen Nuñez、Patrizia Brigidi、Beatrice Vitali、Roberto Gambari、Romeo Romagnoli
DOI:10.1016/s0968-0896(01)00294-2
日期:2002.2
sodium methoxide in refluxing methanol. This provides a general and attractive route to 4-methoxy-6-cyano pyrazolo[3,4-d]pyrimidines from 1-substituted 5-amino pyrazoles 10-19 in two simple steps. Finally, the isosteric replacement of the pyrazole ring atoms to give the imidazole[3,4-d]pyrimidine and triazole [4,5-d] pyrimidine ring systems was examined.