Synthesis and evaluation of some variants of the Nefkens’ reagent

A series of N-substituted phthalimides have been prepared in an effort to explore synthetic variants of the Nefkens’ reagent. Three N-acylphthalimides [R = –CH₃, –CH₂CH₃, and –C(CH₃)₃] were prepared and employed for the protection of a series of representative amines. In addition, an N-methanesulfonylphthalimide and N-(diethylphosphoryl)phthalimide were also prepared. It was determined that among the phthalimides that were prepared N-propanoylphthalimide was the most effective reagent for the protection reaction.