Studies on Geometric Isomerism by Nuclear Magnetic Resonance. IV. Structure of α-Cyano-β-amino-β-alkylacrylic Esters

The NMR spectra of α-cyano-β-amino-β-alkylacrylic esters prepared from α-cyano-β-methoxy-β-alkylacrylic esters and simple amines have been studied. It has been found that these aminoesters, in a variety of solvents, are all present in an intramolecular hydrogen-bonded enamine form with a chelate ring.