Glucose-containing sulfonic acid-catalyzed efficient synthesis of spiro[benzo[g]pyrazolo[3,4-b]quinoline-4,3’-indoline] derivatives

Abstract β-1- N -methyl-imidazole-2,3,4,6-tetrasulfonic-D-glucopyranosyl bisulfate ([Bmim-G-(SO3H)4]+[HSO4]-, NMI-GSA) was used as the efficient catalyst to promote the three-component reaction of 2-hydroxy-1,4-naphthoquinone, isatins and aminopyrazoles to afford a series of spiro[benzo[g]pyrazolo[3,4-b]quinoline-4,3’-indoline] derivatives (4). Six bonds were cleaved while six new bonds (two C-N bonds and four C-C bonds) were formed to constructed a new dihydropyridine ring and a spiro skeleton in one-pot with water as the only one by-product in this highly atom-economic reaction. Two non-toxic products to normal cells have been screened out because of their special high inhibition rate of on MCF-7 cells (> 90%).