179810-58-3Relevant academic research and scientific papers
5-Aminopyrazoles from enolisable ketones and 1-cyano-1-alkylhydrazines
Ryckmans, Thomas,Viehe, Heinz-Gunter,Feneau-Dupont, Janine,Tinant, Bernard,Declercq, Jean-Paul
, p. 1729 - 1734 (2007/10/03)
The reaction of enolisable ketones with 1-alkyl-1-cyanohydrazines leads to the corresponding cyanohydrazones. These compounds cyclise under thermal or mildly basic conditions, furnishing the corresponding 5-aminopyrazoles in good yield. In some cases, the hydrazones cannot be isolated, and the pyrazole derivatives are directly obtained. Hydrazone-enehydrazine tautomerism was observed, but no subsequent [3,3] rearrangement.
Synthesis of 4-acetyl-5(3)-amino-3(5)-methylpyrazoles and pyrazolopyrimidines from diacetylketene N,S-acetal
Dorokhov, V. A.,Komkov, A. V.,Ugrak, B. I.
, p. 1364 - 1368 (2007/10/02)
Isomeric 4-acetyl-5-amino-3-methyl- and 4-acetyl-3-amino-5-methylpyrazoles (2, 3) were formed in the reaction of hydrazones with 3-pentan-2,4-dione (1) (diacetylketene N,S-acetal).Pyrazolopyrimidines (5a,b) were synthesized by condensation of 4-acetyl-5-amino-1,3-dimethylpyrazole (2a) with amide dimethylacetals followed by treatment with ammonium acetate.The structures of the compounds obtained were confirmed by 13C and 15N NMR spectroscopy. - Key words: diacetylketene N,S-acetal; hydrazines; 4-acetyl-5(3)-aminopyrazoles; amide acetals; pyrazolopyrimidines.
