Abstract: As an important protective group of amines and amino acids, tert-butoxycarbonyl(Boc) group was extensively used in organic synthesis. Though many mild and selective reagents could be used, there is still a need for the development of a more simple and convenient method for deprotection. In this paper, a new method for the deprotection of N-Boc group with silica gel in refluxing toluene was reported. The reactions were mostly achieved in 5 h with high yields(75%—98%). N-Boc protected indoline and benzylamine, which are not deprotected with other mild method, could be deprotected with our method in good yields(89% and 95%, respectively). Additionally the deprotection of other carbamates such as Cbz, Fmoc and ethyl carbamate wasn’t observed under same conditions.

Key words: N-Boc deprotection, Silica gel, Selective deprotection