2026-05-15T07:21:06Z https://www.eurjchem.com/index.php/eurjchem/oai

oai:ojs.www.eurjchem.com:article/1369 2016-03-31T05:10:15Z eurjchem:ART driver

Reactions with heterocyclic amidines: Synthesis of several new pyrazolo[1,5-a]pyrimidines and pyrazolo[1,5-a][1,3,5]triazines Abbas-Temirek, Husien Hasan Abo-Bakr, Ahmed Mohammed Amidines Heterocycles Electrophiles Aminopyrazoles Pyrazolotriazines Pyrazolopyrimidines N-Bis(methylthio)methylenecyanamide (1) was allowed to react with ethylcyanoacetate or malononitrile in the presence of potassium carbonate in dimethylsulfoxide to yield the urea derivatives (3a,b), which on treatment with hydrazine hydrater resulted the corresponding aminopyrazole derivatives (4a,b). The cyclic amidine 5-amino-3-ureido-1H-pyrazole-4-carboxylic acid ethyl ester (4a) is found to be useful intermediate for the synthesis of new pyrazolopyrimidine and pyrazolotriazine derivatives (5-22a,b). The chemical structures of the synthesized compounds (3a,b-22a,b) were characterized by their elemental analyses, FT-IR, 1H 13C NMR and mass spectra. Atlanta Publishing House LLC 2016-03-31 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf https://www.eurjchem.com/index.php/eurjchem/article/view/1369 10.5155/eurjchem.7.1.107-114.1369 European Journal of Chemistry; Vol. 7 No. 1 (2016): March 2016; 107-114 2153-2257 2153-2249 eng https://www.eurjchem.com/index.php/eurjchem/article/view/1369/pdf_1369