Abstract The dimerization product of ethyl cyanoacetate (4) reacts with salicylic aldehyde to ethyl β-amino-α-cyano-3-(2-oxo-1-benzopyrano) acrylate (3 a). Cleavage of the lactone, hydrolysis and isomerization occurs with 3 a in aqueos alkaline solution. Acidification yields 2-cyano-methylene-2 H-chromene-carboxylic acid (6 a). The reaction is called “enamine- lactone-rearrangement”.
