An operationally simple and high yielding protocol for the synthesis of polyfunctional pyrazoles has been developed through one-pot, three-component coupling of aldehydes, 1,3-dicarbonyls, and diazo compounds as well as tosyl hydrazones. The reaction proceeds through a tandem Knoevenagel condensation, 1,3-dipolar cycloaddition, and transition metal-free oxidative aromatization reaction sequence utilizing molecular oxygen as a green oxidant. The scope of the reaction was studied by varying the aldehyde, 1,3-dicarbonyl, and diazo component individually.
A mild and efficient
solvent-controlled, metal-free switchable
1,3-dipolar cycloaddition/ring contraction or ring expansion domino
reaction of 3-ylideneoxindoles with in situ-generated α-aryldiazomethanes
has been developed. This domino reaction provided a series of aryl-substituted
3-spirocyclopropyl-2-oxindoles and pyrazoloquinazolinones with excellent
regio- and diastereoselectivity from common substrates under varying
solvent conditions.
A new class of tricyclic heterocycles 4H-benzo[g][1,2,3]triazolo[5,1-c][1,4]oxazocines was synthesized through a Knoevenagel condensation/azide-alkyne cycloaddition reaction cascade in one-pot operation. These eight membered ring containing heterocycles exhibited moderately high anticancer activity against four cancer cell lines; human cervix cancer cell line (HeLa), human prostate cancer cell line (DU145), human breast cancer cell line (MCF-7) and human breast adenocarcinoma epithelial cell line (MDA-MB-231). Our results indicate that these compounds have a weak cytotoxic effect on normal human mammary epithelial cell line (MCF-10A). Cell cycle and apoptosis assay indicate that they inhibit the cell cycle at the G2/M phase and induce apoptosis. Through the RED assay, it is evident that they have potential to inhibit pBR 322 plasmid DNA cleavage by BamH1. UV-visible, fluorescence titration and viscosity studies suggested that these compounds possess DNA binding affinity.
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