Synthesis and evaluation of deglycobleomycin A2 analogues containing a tertiary N-methyl amide and simple ester replacement for the l-histidine secondary amide: Direct functional characterization of the requirement for secondary amide metal complexation
作者:Dale L. Boger、Shuji Teramoto、Hui Cai
DOI:10.1016/0968-0896(95)00183-2
日期:1996.2
indistinguishable from those of deglycobleomycin A2 (2) confirming that the distinctions between bleomycin A2 (1) and deglycobleomycin (2) are due to the removal of the disaccharide and not the introduction of the L-histidine free beta-hydroxy group. The agents 4 and 5 containing a tertiary N-methyl amide and ester in place of the L-histidine secondary amide were found to cleave duplex DNA but to do so in a nonsequence
详述了3-5个脱糖霉素A2(2)的类似物的合成和比较研究,它们直接解决了L-组氨酸仲酰胺的重要性。试剂3仅缺少脱糖霉素A2的L-组氨酸β-羟基,并且相应的试剂4和5掺入叔N-甲基酰胺和简单的酯代替L-组氨酸仲酰胺。3的DNA切割特性与脱糖霉素A2(2)基本上没有区别,这证实了博莱霉素A2(1)和脱糖霉素(2)之间的区别是由于去除了二糖而不是引入了不含L-组氨酸的β-羟基。发现含有叔N-甲基酰胺和酯代替L-组氨酸仲酰胺的试剂4和5可以裂解双链DNA,但以非序列选择性方式裂解,效率大大降低,双链至单链减少裂解率仅略大于游离铁本身。后面这些观察结果确定了L-组氨酸仲酰胺的功能要求,并与L-组氨酸去质子化的仲酰胺是功能性金属螯合和活性所必需的建议相一致。