A green one-pot synthesis of spironaphthopyrano [1,2-b]indeno-7,3′-indolines

For the first time, spironaphthopyrano[1,2-b]indeno-7,3'-indolines were prepared by cyclo-condensation of 1,3-indandione, isatin, and 2-naphthol under solvent-free and catalyst-free conditions. This procedure is not only environmentally benign but is also a simple, one-pot, three-component procedure with the advantages of easy workup and mild reaction conditions. The same reaction was investigated with other beta-diketones instead of 1,3-indandione, and the results are reported. The compounds synthesized were screened for antimicrobial activity.