79476-38-3Relevant academic research and scientific papers
Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents
Jansa, Josef,Schmidt, Ramona,Mamuye, Ashenafi Damtew,Castoldi, Laura,Roller, Alexander,Pace, Vittorio,Holzer, Wolfgang
supporting information, p. 895 - 902 (2017/06/21)
A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I2/HIO3 gives the appropriate 4-iodopyrazoles which served as starting materials for different cross-coupling reactions. Finally, Negishi cross-coupling employing organozinc halides and Pd catalysts turned out to be the method of choice to obtain the desired tetrasubstituted pyrazoles. The formation of different unexpected reaction products is described. Detailed NMR spectroscopic investigations (1H, 13C, 15N) were undertaken with all products prepared. Moreover, the structure of a condensation product was confirmed by crystal structure analysis.
REACTION OF 1-PYRIDYL-1,3-BUTANEDIONES AND 1,3-DIPYRIDYL-1,3-PROPANEDIONES
Ferles, Miloslav,Kafka, Stanislav,Silhankova, Alexandra,Sputova, Michaela
, p. 1167 - 1172 (2007/10/02)
Reduction of diketones I with zinc and formic acid gives monoketones II.Diketones Ia, IIIb, IIIc are converted with hydrazines to pyrazoles VIa, IVa, IVb, V.Methiodides VII are reduced with sodium borohydride to derivatives of 1-methyl-3-piperideine VIII-
