67985-59-5Relevant academic research and scientific papers
Unexpected formation of bis-pyrazolyl derivatives by solid support coupled with microwave irradiation
Esteves-Souza, Andressa,Echevarría, Aurea,Vencato, Ivo,Jimeno, María Luisa,Elguero, José
, p. 6147 - 6153 (2001)
Starting from 1,3-dimethyl-5-aminopyrazole 1 and p-substituted benzaldehydes 2 (R=H, CH3, NO2), four different compounds have been obtained: the Schiff bases 4, a bis-pyrazolyl Schiff base 6a (R=H), the expected bispyrazolo[3,4-b;4′,3′-e]pyridine 7b (R=CH3) and the carbinol derived from the Schiff base 8c (R=NO2). The products have been characterised by MS, NMR (1H and 13C) and X-ray crystallography (in the case of 6a). A proposal for the relationships between the different compounds and a possible mechanism is presented.
Blue electroluminescence of novel pyrazoloquinoline and bispyrazolopyridine derivatives in doped polymer matrices
He,Milburn,Danel,Puchala,Tomasik,Rasala
, p. 2323 - 2325 (1997)
Blue electroluminescence has been demonstrated using novel materials 1,3-diphenyl-4-methyl-1H-pyrazolo[3,4-b]quinoline (PAQ4) and 4-phenyl-1,3,5,7-tetramethyl-1,7-dihydrodipyrazolo[3,4-b;4′,3′-e] pyridine (PAP1) for the first time. The peak maxima of their electroluminescent spectra were at 442 nm (ca. 20 nm shift from its photoluminescent maximum) for PAQ4 and 425 nm (within the same spectral range as the photoluminescence) for PAP1.
A mild method for the synthesis of bis-pyrazolo[3,4-b:4′,3′-e]pyridine derivatives
Qiu, Rui,Qiao, Shujia,Peng, Boyu,Long, Jiajia,Yin, Guodong
supporting information, p. 3884 - 3888 (2018/09/27)
A mild and efficient method for the synthesis of bispyrazolo[3,4-b:4′,3′-e]pyridines from 5-aminopyrazoles and aromatic aldehydes using an inexpensive FeCl3 catalyst is reported. The reaction temperature was reduced from 220–250 °C to 130 °C compared to conventional methods. A large proportion of the products precipitated directly from the mixture at room temperature. Aliphatic and α,β-unsaturated aldehydes selectively resulted in formation of the corresponding 1H-pyrazolo[3,4-b]pyridine derivatives. A possible domino reaction mechanism was also proposed. Several aryl alkynyl groups were introduced to these tricyclic molecules via the Sonogashira coupling reaction.
