Synthesis and antischistosomal activity of certain pyrazolo[1,5-a]pyrimidines

Abstract

Several 7-hydroxypyrazolo[1,5-a]pyrimidines (1-21), 7-mercaptopyrazolo[1,5-a]pyrimidines (37-49), and 4-alkylpyrazolo[1,5-a]pyrimidin-7-ones (50-55) and the corresponding 4-alkylpyrazolo[1,5-a]pyrimidine-7-thiones (56-60) were synthesized and tested for antischistosomal activity against Schistosoma mansoni. Of the compounds examined, the greatest degree of activity in vitro was found with the 7-mercaptopyrazolo[1,5-a]pyrimidines. In particular, compounds 37 and 47 proved lethal at 100 micrograms/mL after an exposure of only 1 h. The 7-hydroxypyrazolo[1,5-a]-pyrimidines were not as active. None of the compounds exhibiting in vitro activity were active against S. mansoni in vivo.

Synthesis, Characterization and Biological Evaluation of some Novel Pyrazolo[1,5-a]Pyrimidine Derivatives

“…The heterocyclic fusion of pyrimidine ring and pyrazole ring resulted in formation of pyrazolopyrimidines, the structural analogues of biogenic purine class, undoubtedly, has high significance in the field of pharmaceutical and biotechnological sciences with wide spectrum of biological activities and its several derivatives [2][3][4]. Several compounds of this class display interesting antitrypanosomal [4] and antischistosomal activities [6]. They are used as HMG-CoA reductaseinhibitors [7], COX-2 selective inhibitors [8], 30,50-cyclic-AMP phosphodiesteraseinhibitors [9], CRF1 antagonists [10][11], selective peripheral benzodiazepine receptor ligands [12][13][14][15][16], potassium channel [17] and histamine-3 receptor ligands [18], CDK9 inhibitor [19]and antianxiety agents [20].…”

The synthesis of new pyrazolo[1,5-a]pyrimidine derivatives

“…[10][11][12][13][14][15] The most common methods for synthesis of pyrazolo [1,5-a]pyrimidine derivatives are cyclocondensations of 5-aminopyrazoles with bifunctional reagents. 16 The synthesis of 2-anilinopyrazolo [1,5-a]pyrimidine derivatives as c-Src kinase inhibitors has been reported. 17 In continuation of our studies on the synthesis of bi-, tri-and tetracyclic heterocycles, [18][19][20][21][22][23][24][25] herein we report a convenient method for the synthesis of new pyrazolo [1,5-a]pyrimidine derivatives with possible pharmaceutical applications.…”

Regioselective Syntheses of 3-Benzyl-Substituted 7H-Thiazolo[3,2-a]pyrimidine-7-ones through Palladium-Catalyzed Heteroannulation of Acetylenic Compounds

“…In general, heterocycles encompassing a pyrimidine unit have found applications in a wide spectrum of biological and therapeutic areas [17,18]. Thus, the heterocyclic system resulting from annulation of a pyrimidine ring on the biologically versatile thiazole nucleus is an attractive scaffold to be utilized for exploiting chemical diversity.…”