A proton n.m.r. method has been used to monitor racemisation during the coupling of -methylated amino acids by the diphenylphosphinic mixed anhydride procedure. No racemisation was observed when urethane protection was employed, but use of the benzoyl group led to extensive racemisation. The reagent was subsequently used for the assembly of several extensively -methylated peptides.
在通过二苯基次膦混合酸酐法偶联-甲基化
氨基酸的过程中,已经使用质子核磁共振法监测外消旋化。当采用
氨基甲酸酯保护时未观察到外消旋化,但是使用苯甲酰基导致广泛的外消旋化。该试剂随后用于组装几种完全甲基化的肽。