An efficient and green synthesis of highly functionalized N-methyl-2-nitro-aryl-1H-benzo[f]chromen-3-amine derivatives under catalyst-free conditions

A highly efficient and environmentally benign protocol has been developed for the construction of various potentially biologically active N-methyl-2-nitro-aryl-1H-benzo[f]chromen-3-amine derivatives using one-pot, multi-component cascade reaction of various naphthalen-2-ol, aldehydes, and (E)-N-methyl-1-(methylthio)-2-nitroethenamine under catalyst-free conditions in the presence of green solvent medium (ethanol-water) is described. The significant features of this protocol are short reaction times, provide excellent yields, avoidance of toxic solvents and catalysts, no column chromatographic purification, atom-economy and uses ethanol-water as a green solvent which is considered to be relatively environmentally benign. This is the first example of the condensation of naphthalen-2-ol, aldehydes, and (E)-N-methyl-1-(methylthio)-2-nitroethenamine to provide a novel series of 1H-benzo[f]chromen-3-amine derivatives.

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