Protecting-group strategies for the synthesis of N 4-substituted and N 1,N 8-disubstituted spermidines, exemplified by hirudonine
作者:Bernard T. Golding、Andrew Mitchinson、William Clegg、Mark R. J. Elsegood、Roger J. Griffin
DOI:10.1039/a806355i
日期:——
Methods are described for the preparation of derivatives of the polyamines 1,4-diaminobutane (putrescine) and N-(3-aminopropyl)-1,4-diaminobutane (spermidine) in which a particular amino group is modified with, e.g., a guanidino function. Specific amino groups in these polyamines were protected as N-trifluoroacetyl and N-4-azidobenzyloxycarbonyl derivatives, which were unmasked chemoselectively using methanolic ammonia and dithiothreitol–triethylamine, respectively. Guanidino functions were introduced by an improved procedure in which an amino group was treated with 3,5-dimethyl-N-nitro-1H-pyrazole-1-carboximidamide in methanol to give a nitroguanidine derivative, from which the nitro group was removed by catalytic transfer hydrogenation. The methodology is exemplified by the development of efficient preparative routes to agmatine and hirudonine. The integrity of the sequence of protection/deprotection leading to hirudonine was confirmed by a crystal-structure analysis of its sulfate. The effect of selected compounds on the uptake of putrescine into rat lung cells was determined and showed that N
4-(4-azidobenzyloxycarbonyl)spermidine was the best inhibitor (Ki = 3.4 µM).
本文描述了制备多胺衍生物1,4-二氨基丁烷(腐胺)和N-(3-氨基丙基)-1,4-二氨基丁烷(精胺)的方法,其中特定的氨基被修饰为胍基等官能团。在这些多胺中,特定的氨基被保护成N-三氟乙酰基和N-4-叠氮苄氧羰基衍生物,并分别使用甲醇氨和二硫苏糖醇-三乙胺选择性地脱去保护。通过改进的方法引入胍基官能团,其中氨基与3,5-二甲基-N-硝基-1H-吡唑-1-羧酰亚胺在甲醇中反应生成硝基胍衍生物,然后通过催化转移氢化除去硝基。该方法以开发高效的制备路线至胍氨酸和蛭素为例。保护/去保护序列的完整性通过其硫酸盐的晶体结构分析得到了证实。评估了选定化合物对大鼠肺细胞摄取腐胺的影响,并显示N-4-(4-叠氮苄氧羰基)精胺是最好的抑制剂(Ki = 3.4 µM)。