Simple, Efficient, and Catalyst-Free Synthesis of (2-Amino-4H-1-benzopyran-4-yl)phosphonates in Polyethylene Glycol

Several (2-amino-4H-1-benzopyran-4-yl)phosphonates were efficiently synthesized by employing a multicomponent protocol involving a salicylaldehyde, malononitrile or ethyl cyanoacetate, and a trialkyl phosphite in polyethylene glycol. The latter could be recovered and re-used. No additional solvent or catalyst was required. To the best of our knowledge, this is the first report of the one-pot preparation of (2-amino-4H-1-benzopyran-4-yl)phosphonic acid dimethyl esters.