反应详情

A number of different blocking agents can be used to block the amine group on the glutamic acid. These blocking agents include acyl-type protecting groups, urethan protecting groups, alkyl-type protecting groups, and arylidene-type protecting groups. Alternatively, rather than using blocking agents, the amine group can be protonated to block its functionality. Preferably, blocking of the glutamic acid is achieved by reacting it with carbobenzoxy chloride in an aqueous alkaline solution to form N-carbobenzoxy glutamic acid, which is commonly referred to as Z-glutamic acid. This reaction is inexpensive and provides about a 90% yield of Z-glutamic acid. Alternatively, Z-glutamic acid can be obtained from Aldrich Chemical Company, 1001 West Saint Paul Avenue, Milwaukee, Wis. 53233. Z-glutamic acid has the following structure: