91099-29-5Relevant academic research and scientific papers
Catalyst-free Biginelli-type synthesis of new functionalized 4,7-dihydropyrazolo[1,5-: A] pyrimidines
Kolosov, Maksim A.,Beloborodov, Dmitriy A.,Orlov, Valeriy D.,Dotsenko, Victor V.
, p. 7573 - 7579 (2016/09/12)
The Biginelli-type reaction of 5-amino-3-arylpyrazole-4-carbonitriles with aldehydes and 1,3-dicarbonyl compounds was studied in detail. We found that the reaction requires no catalysts and proceeds in boiling DMF to give 2-aryl-6-RC(O)-4,7-dihydropyrazolo[1,5-a]pyrimidin-3-carbonitriles in good yields. The reaction of aminopyrazoles with dicarbonyls leading to 6-unsubstituted pyrazolo[1,5-a]pyrimidines proceeds competitively and becomes the dominant process under acid-promoted conditions. 2-Aryl-8-oxo-4,5,6,7,8,9-hexahydropyrazolo[5,1-b]quinazolin-3-carbonitriles were obtained under catalyst-free conditions in up to 80% yields starting from 5-amino-3-arylpyrazole-4-carbonitriles, aldehydes and 1,3-cyclohexanedione.
Studies on 5-Aminopyrazole Derivatives. Synthesis of Some New Fused Pyrazole Derivatives
Zayed, Ezzat Mohamed,Ghozlan, Said Ahmed Soliman,Ibrahim, Abdel-Azim Hady
, p. 431 - 436 (2007/10/02)
5-Amino-4-cyano-3-phenylpyrazole (1) reacts with acrylonitrile or ethyl acrylate to yield 4-cyano-3-phenyl-4,5,6,7-tetrahydro-5-oxopyrazolo--pyrimidine (2).With urea, thiourea and ethyl acetoacetate 1 gives the pyrazolopyrimidine derivatives 6a, 6b
