Solventless Synthesis of <i>N</i>-Protected Amino Acids in a Ball Mill

Abstract

An eco-friendly methodology for preparing carbamate N-protected α-amino acids is described using ball-milling technology. Some β-amino acids were also investigated in this study. This solvent-free methodology gave Boc-, Z-, and Fmoc-N-protected compounds in good to excellent yields with improved environmental impact compared to classical syntheses in solution. Different planetary ball mills were employed. The results are also discussed according to the different process parameters (grinding material, number of balls, rotation speed).