Using p-(p′-methoxy-phenylazo)-benzyloxycarbonyl-(MZ-) and p-nitrobenzyl-(NB-) as blocking groups for the ct-amino- and a-carboxylic functions respectively, a completely protected pentapeptide unit, occurring in tyrocidine A, has been prepared: MZ-L-Phe-D-Phe-L-Asp(OCH,)-L-Glu(OCH,)-L-Tyr(OAc) ONB. The p-nitrobenzyl-ester group is very resistant towards HBr in acetic acid, the reagent used for intermediary
使用对-(对'-甲氧基-苯基偶氮)-苄氧基羰基-(MZ-)和对-硝基苄基-(NB-)分别作为ct-
氨基和α-羧基官能团的封闭基团,出现了一个完全受保护的五肽单元在
酪氨酸A中已制备:MZ-L-Phe-D-Phe-L-Asp(OCH,)-L-Glu(OCH,)-L-Tyr(OAc)ONB。对硝基苄基酯基对
乙酸中的HBr具有很强的抵抗力,
乙酸是用于MZ基团中间分裂的试剂。借助于POCl 3,+
三乙胺或通过二环己基-碳二
亚胺形成肽键。所有含有MZ基团的产物均以结晶状态获得。