title: 1H-pyrazolo[4,3-d]pyrimidine-7(6H)-one and 5H-pyrazolo[4,3-d] 1,2,3-triazin-4(3H)-one derivatives. Synthesis and in vitro biological activity at adenosine A1 and A2a receptors.
abstract: The affinity of newly synthesized 1H-pyrazolo[4,3-d] pyrimidine-7 (6H)- one (5a-f) and 5H-pyrazolo[4,3-d]1,2,3,-triazin-4(3H)-one (6a-i) derivatives for A1 and A2a adenosine receptors was investigated in rat cerebral membranes. The compounds showed affinities in the micromolar range for both adenosine A1 and A2a receptors. In particular 5d was the most interesting compound and showed some degree of selectivity for the A1 receptor (Ki values being 2 mumol/l; A1/A2a ratio < 0.021). The present study provides useful information for a better understanding of the structure-activity relationships of antagonists at adenosine receptors.
authors: P G
authors: PG
authors: Baraldi
authors: B
authors: B
authors: Cacciari
authors: A
authors: A
authors: Dalpiaz
authors: S
authors: S
authors: Dionisotti
authors: C
authors: C
authors: Zocchi
authors: M J
authors: MJ
authors: Pineda de las Infantas
authors: G
authors: G
authors: Spalluto
authors: K
authors: K
authors: Varani
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000478:Alkylation; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008566:Membranes / Q000378:metabolism; D010627:Phenethylamines; D058915:Purinergic P1 Receptor Antagonists; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014227:Triazines / Q000138:chemical synthesis* / Q000494:pharmacology
chemical_list: D010627:Phenethylamines; D058915:Purinergic P1 Receptor Antagonists; D011720:Pyrazoles; D011743:Pyrimidines; D014227:Triazines; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C027513:N(6)-cyclohexyladenosine; D000241:Adenosine