Controlled Switching of Multicomponent Heterocyclizations of 5-Amino- N-arylpyrazole-4-carboxamides, 1,3-Cyclohexanediones, and Aldehydes.

Chebanov, Valentin A.; Saraev, Vyacheslav E.; Shishkina, Svetlana V.; Shishkin, Oleg V.; Musatov, Vladimir I.; Desenko, Sergey M.

Multicomponent heterocyclization of 5-amino- N-arylpyrazole-4-carboxamides, 1,3-cyclohexanediones, and aromatic aldehydes was studied, and reaction conditions allowing selective switching between two directions were found. When the reaction was carried out under thermal heating or ultrasonication at room temperature, formation of linear pyrazoloquinoline-3-carboxamides was observed. Isomeric angular heterocycles were obtained by ultrasonic-assisted synthesis at ambient temperature in the presence of HCl catalyst. Treatment with 2 equiv. of 1,3-diketone in boiling N, N-dimethylformamide/HCl gave a mixture of pyrazoloquinoline-3-carboxamides and unusual acridin-10-yl-pyrazole-4-carboxamides, which showed hindered rotation of the pyrazole fragment around the C-N bond.

European Journal of Organic Chemistry, 2012, Vol 2012, Issue 28, p5515

1434-193X

Academic Journal

10.1002/ejoc.201200669