Synthesis of N-aryl-5-amino-4-cyanopyrazole derivatives as potent xanthine oxidase inhibitors

Synthesis, characterization and crystal structures of hydrazone compounds derived from isonicotinohydrazide

“…The shorter distances of the C-N bonds and the longer distances of the C=O bonds for the -C(O)-NH-units than usual, suggests the presence of conjugation effects in the molecules. The remaining bond lengths in the compounds are comparable to each other, and within normal values [17,18]. The dihedral angles between the benzene and pyridine rings are 5.3(3)° for 1, and 4.9(3)° and 1.1(3)° for 2.…”

Synthesis and Biological Activities of Novel 1,7-dihydropyrazolo[3,4-d]imidazo[1,2-f]pyrimidines

“…This later reacts then with substituted hydrazine to give the aminocyanopyrazole 2. Treatment of 2 with orthoester in the presence of catalytic amount of acid furnished the corresponding cyano-pyrazoloimidates 3 which subsequently were transformed to the corresponding amino pyrazolopyrimidines 4 upon treatment with ammoniac [5,[15][16][17]. Reaction of compound 4 with α-bromoacetophenone in the presence of a catalytic amount of PTSA (5 mol% The reaction occurs by a primary amino group intercepts a bromine atom liberating HBr, followed by an intracyclisation and elimination of a water molecule to give 1,7-dihydropyrazolo [3,4-d]imidazo[1,2-f] pyrimidines 5a-i.…”

Synthesis and Isomerization of Some Novel Pyrazolopyrimidine and Pyrazolotriazolopyrimidine Derivatives

“…257-259 °C. [4,3-e] [1,2,4]triazolo [4,3-c]pyrimidine (9): Compound 3 (1.20 g, 0.005 mol) was heated under reflux temperature in triethyl orthoformate (40 mL) for 5 h. The reaction mixture was kept at room temperature overnight, then the solvent was evaporated to dryness and the remaining solid was purified on TLC plate using chloroform: methanol (9:1) as an eluent to separate compound 9 as the major product. Yield 79%, m.p.…”

“…Pyrazolo [3,4-d]pyrimidines and their related fused heterocycles are of considerable significance chemical and pharmaceutical utility as purine analogs [3] and many of their derivatives were reported to possess antiviral [1,4] antimicrobial [2,5] anti-inflammatory [6,7] anticancer [8] and xanthine oxidase inhibitor [9] activities.…”