5-acetamido-7,8,9-tri-O-acetyl-2,6-anhydro-4-[N'-(tertbutoxycarbonyl)thiourea]-3,4,5-trideoxy-D-glycero-D-galactonon-2-enonic acid methyl ester 、
N-叔丁氧羰基-1,4-丁二胺 在
三乙胺 、 mercury dichloride 作用下,
以
N,N-二甲基甲酰胺 为溶剂,
反应 2.0h,
以74%的产率得到5-acetamido-7,8,9-tri-O-acetyl-2,6-anhydro-4-[N'-(tertbutoxycarbonyl)-N''-(4-tert-butoxycarbonylaminobutyl)guanidino]-3,4,5-trideoxy-D-glycero-D-galacto-non-2-enonic acid methyl ester