LiOH-mediated N-monoalkylation of α-amino acid esters and a dipeptide ester using activated alkyl bromides

Selective N-monoalkylation of α-amino esters with activated alkyl bromides was studied using various alkali or alkali earth metal bases. In the production of N-monoalkylated amino ester derivatives and suppression of N,N-dialkylation, lithium hydroxide was more effective than any other alkali or alkali earth bases examined. Using this protocol, a variety of N-alkylated α-amino esters and even dipeptide esters have been successfully prepared using various activated alkyl bromides.