Efficient deprotection of N^G-tosylarginine with a thioanisole–trifluoromethanesulphonic acid system

Abstract

The tosyl group attached at the guanidino function of arginine can be efficiently cleaved by a thioanisole–trifluoromethanesulphonic acid system, which can deprotect O-2,6-dichlorobenzyltyrosine without the formation of O-to-C rearrangement products; the NG-mesitylene-2-sulphonyl group was also cleaved by a thioanisole–trifluoroacetic acid system.