Potential Purine Antagonists. VI. Synthesis of 1-Alkyl- and 1-Aryl-4-substituted Pyrazolo[3,4-d]pyrimidines^1,2

3-Aminopyrroles and their application in the synthesis of pyrrolo[3,2-d]pyrimidine (9-deazapurine) derivatives

“…To confirm the structure of compound 12 an independent route was followed, compound 4a was refluxed in boiling formic acid to produce pyrrolopyrimidinone-7-carboxamide 13. Compound 13 was refluxed in phosphorus oxychloride to obtain 4-chloropyrrolopyrimidines 14 24 , then reacting compound 14 with aniline, the pyrrolo[3,2-d]pyrimidine 12 (65 %) was isolated, whose spectral characteristics were completely coincident with the samples obtained before (Scheme 3). Under the same reaction conditions, the amidines 7b and 8b reacted with aniline to afford the bicyclic compound 4-oxo-3-phenylpyrrolo[3,2-d]pyrimidine 15.…”

Two approaches to a new heterocyclic system of pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine

“…The cyclization of 4a to 5a, via elimination of a molecule of water, proceeds upon reflux in bromobenzene for 3-4 hours. The structure of pyrazolotriazolopyrimidine 5a was supported by its 1 3,4 with acylhydrazines and studying their cyclization reactions. The energy preference of the amino form of the acylhydrazines 7 over the possible imino tautomer is confirmed by their Of certain interest is the mode of crystal packing for compound 5g.…”

“…4 By treatment of 5-amino-1H-pyrazole-4-carbonitriles 1 with ethyl orthoformate, imidoesters 2 were prepared following a literature method. 2 Chloropyrazolopyrimidines 6 were obtained by the method described by Robins.…”

“…The imidoesters 2 obtained by coupling 5-amino-1H-pyrazole-4-carbonitriles 1 with triethyl orthoformate react with amines to form a heterocyclic pyrazolo [3,4-d]pyrimidine system, 1,2 the compounds of which display interesting chemical properties [1][2][3][4][5][6] and possess a wide spectrum of biological activities. [7][8][9][10][11] We have presumed that by employing hydrazides as the amine components of this reaction, the cascade heterocyclization 2→3→4→5 may occur to afford derivatives of a new heterocyclic system of pyrazolo [4,3- …”

Symmetrically and Unsymmetrically Bridged Methylenebis(allopurinols): Synthesis of Dimeric Potential Anti-Gout Drugs

“…The methoxy group can subsequently undergo S N Ar nucleophilic displacement reactions, which are particularly advantageous for the synthesis of N(1)-and N(2)-glycosylated allopurinol nucleosides [13,16,17]. Cleavage of the methoxy function with acid always bears the risk of concomitant Nglycosylic bond cleavage.…”