Chemistry of Amino Acids. VII. The Synthesis and Spectral Studies of Some 2-Piperidones bearing β-Keto Ester Groups

Abstract

Some 2-piperidones (IX and X) bearing β-keto ester groups were synthesized from the methyl esters (V) of alanine and phenylalanine according to a route similar to that described in our previous paper. Spectral studies (infrared, ultraviolet and nuclear magnetic resonance) revealed that these β-keto esters (IX and X) mainly exist in the chelated enolic tautomer (E) both in the solid state and in solution. The NMR spectra of some indole derivatives (XI-XVI) were also investigated.