Novel water soluble carbodiimides, and intermediates or derivatives thereof, such as isoureas or isothioureas, are described. A particularly preferred embodiment is bis[4-(2,2-dimethyl-1,3-dioxolyl)methyl] carbodiimide (BDDC), which can be synthesized efficiently from 1,2-isopropylideneglycerol (solketal). The isoureas are effective esterifying agents. The corresponding N-protected amino acid tert-butyl, benzyl, isopropyl, ethyl, and methyl esters can be synthesized in high yield under neutral conditions, with no urea residue after simply washing with aqueous acid. Amino acid couplings utilizing carbodiimide embodiments give peptides in good yield, free of carbodiimide by-products, after washing with dilute acid, while racemization-free peptides are also obtained.
本文介绍了一种新型的
水溶性羰基二
亚胺化合物,以及其中间体或衍
生物,如异
脲或异
硫脲。特别优选的是双[4-(2,2-二甲基-1,3-二氧戊基)甲基]羰基二
亚胺(
BDDC),可以从1,2-异丙基亚
甘醇(索尔克特)高效合成。异
脲是有效的酯化试剂。在中性条件下,可以高产率地合成相应的N-保护
氨基酸叔丁基、苄基、异丙基、乙基和甲基酯,仅需用
水酸洗后即可去除
尿素残留物。利用羰基二
亚胺的衍
生物进行
氨基酸偶联反应,可以得到产率良好的肽,用稀酸洗涤后无羰基二
亚胺副产物,同时还可获得无旋光异构体的肽。