Synthesis of pyrazolo[4′,3′:3,4]pyrido[1,2-a]benzimidazoles and related new ring systems by tandem cyclisation of vic-alkynylpyrazole-4-carbaldehydes with (het)aryl-1,2-diamines and investigation of their optical properties

Add time:08/06/2019    Source:sciencedirect.com

The synthesis of 2H- and 3H-pyrazolo[4′,3′:3,4]pyrido[1,2-a]benzimidazole derivatives from 3-alkynyl- or 5-alkynylpyrazole-4-carbaldehydes and benzene-1,2-diamines was carried out using copper-free tandem cyclisation. When 2,3-diaminopyridine was used as the diamine component in this type of tandem cyclisation, 3H-pyrazolo[4,3-c]imidazo[1,2-a:5,4-b′]dipyridine derivatives were obtained. Copper catalysis and microwave activation were required for the reaction of 5-alkynylpyrazole-4-carbaldehydes and 1,8-naphthalenediamine, affording the corresponding 13,13a-dihydro-3H-pyrazolo[4′,3′:3,4]pyrido[1,2-a]perimidines. The structure assignments were based on data from 1H, 13C and 15N spectroscopy and single-crystal X-ray diffraction analyses. The optical properties of the obtained new heterocyclic derivatives were studied by UV–vis and fluorescence spectroscopy.

We also recommend Trading Suppliers and Manufacturers of N1-Phenyl-4-(trifluoroMethyl)benzene-1,2-diaMine (cas 1651-43-0). Pls Click Website Link as below: cas 1651-43-0 suppliers

Prev:Synthèse et caractérisation physico-chimique de polyacrylates de ω-perfluorooctyl-alkyle: effet pair–impair
Next:Chemical-genetic interaction landscape of mono-(2-ethylhexyl)-phthalate using chemogenomic profiling in yeast)