New synthesis of alkyl esters of β-amino-acids

A new method is described for the preparation of ethyl esters of β-aryl-β-aminoacids, depending on condensation of monoethyl malonate with aromatic aldehydes in the presence of alcoholic ammonia.

The method serves for preparation of the ethyl esters of β-phenyl-β-alanine, β-(3-nitrophenyl)-β-alanine, and β-amino-β-piperonylpropionic acid, and of monoethyl β-amino-β-piperonylisocuccinate.

The esters were converted into 4-aryldihydrouracils by boiling with urea solution.

Ethyl esters were prepared by the standard method from N-benzoyl derivagives of β-aminoacids.