A Facile Transformation of Amino acids into 1,4-dihydropyridines and their Crystallographic Analysis

A facile transformation of amino acids into substituted 1,4-dihydropyridines (1,4-DHP) is reported. The natural amino acids were converted into gamma-amino beta-keto esters and used for the synthesis of substituted 1,4-dihydropyridines from the Hantzsch reaction. Using amino acids as starting materials, a variety of dihydropyridine derivatives have been synthesized and isolated in good yields. This method is found to be efficient and compatible with various amino acid side-chains and amine protecting groups. Results reported here suggested that amino acids can be used to synthesize highly versatile heterocyclic 1,4-dihydropyridine derivatives, without using any catalyst.