PEG-Mediated Catalyst-free Facile Protocol for N-Boc Protection of Amines under Solvent-free Conditions

We have reported an efficient and eco-friendly protocol for the protection of various structurally and electronically divergent aryl and aliphatic amines using (Boc)2O in the presence of PEG-400 under solvent-free conditions at room temperature. Protection and deprotection of functional groups are important and frequently needed exercise in modern organic chemistry. Particularly protection of amines is very important due to their high nucliophilicity and basicity. The reaction occurred and giving excellent yields with low as well as high molecular weight PEGs. The study find that the reaction proceeded best under solvent-free conditions rather than using solvents. The best result was obtained with 0.5 mL of PEG - 400 for 3 mmol of aniline, under solvent-free conditions at room temperature within 5 min. This is a very general and environmentally benign eco-friendly procedure, which would prove beneficial to both academic and industrial fields.