Synthesis of acyclo C-Nucleosides of H₁-antihistaminic 4-substituted [1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones

Abstract

Two series of aldose N-(3-substituted-4-oxo-3,4-dihydroquinazolin-2-yl)hydrazones were prepared by the reaction of each of the aldoses with the appropriate 2-hydrazino-3-substituted-quinazolin-4(3H)-ones. Oxidative cyclisation of these aldose hydrazones with ferric chloride in ethanol yielded the title acyclo C-nucleosides.

Synthesis of New 3,7,9-Trisubstituted Pyrazolo[4,3-e][1,2,4]Triazolo[4,3-c] Pyrimidines Acyclo C-Nucleosides via Oxidative Cyclisation

“…For example, several 3-and/or 5-substituted-7H-pyrazolo [4,3-e] [1,2,4] triazolo [4,3-c]pyrimidines and the isomeric pyrazolo [4,3- e] [1,2,4]triazolo [1,5-c]pyrimidine ring system possess one of the structural requirements for compounds that behave as selective antagonists for human A 2A and A 3 adenosine receptor subtypes. 11 As a result of these findings and in continuation of our previous work on the synthesis of fused triazoles, [12][13][14][15][16] we report herein the synthesis of 3,7,9-trisubstituted pyrazolo [4,3-e] [1,2,4]triazolo [4,3-c] pyrimidines, namely, 3-substituted-7,9diphenyl pyrazolo [4,3-e] [1,2,4]triazolo [4,3-c]pyrimidine acyclo C-nucleosides via tandem generation and 1,5-electrocyclisation of their respective C-(1-alditolyl)N- (1,3-diphenylpyrazolo[3,4-d] pyrimidin-4-yl)nitrilimines which have been hitherto unreported.…”

Spin Canting and Topological Ferrimagnetism in Two Manganese(II) Coordination Polymers Generated by In Situ Solvothermal Ligand Reactions

“…It is not surprising to observe the hydrolysis reaction of 2-pyridylamidrazone to pa at high temperature and pressure, since amidrazone groups can be hydrolyzed to carboxylate groups under common reaction conditions. [15] Presumably, Mn II ions promote the hydrolysis of 2-pyridylamidrazone. [16] (Figure 1b), in which each pa acts as a tridentate ligand and each carboxylate group bridges two SBUs in a syn-anti coordination mode (Mn···Mn 6.080 Å).…”