Synthesis of steroidal dendrimers modified by ‘click’ chemistry with PAMAM dendrons as unimolecular micelles
作者:Delia Soto-Castro、Nancy E. Magaña-Vergara、Norberto Farfán、Rosa Santillan
DOI:10.1016/j.tetlet.2013.12.066
日期:2014.1
Novel Fréchet–PAMAM hybrid dendrimers linked by triazole units as unimolecular micelles with a hydrophobic core surrounded by a hydrophilic shell were prepared. The dendritic cores with 3 and 6 alkyne terminal groups were synthesized from 1,3,5-tribromomethyl-benzene (tBrMeB), in one case by direct coupling with 17α-ethynylestradiol (EE); in the second one the tBrMeB was reacted with bis(hydroxymethyl)
制备了由三唑单元连接为单分子胶束,疏水核被亲水壳包围的新型Fréchet-PAMAM杂化树状聚合物。由1,3,5-三溴甲基苯(t BrMeB)合成一种带有3个和6个炔基末端基团的树突状核,在一种情况下是通过与17α-乙炔基雌二醇(EE)直接偶联;在第二个反应中,使t BrMeB与双(羟甲基)苯酚反应,然后对羟基进行氯化,然后偶联至EE。通过这种策略,可以通过在卤代末端上进一步取代双(羟甲基)苯酚(如Fréchet树状大分子)来生长核。所用的亲水壳是0.5代和1.5代的PAMAM型树突,以叠氮化物为焦点,叔-丁基酯作为端基。通过在选定的树枝状结构中的叠氮化物与疏水性核中的炔烃末端之间进行环加成反应,获得1,4-二取代的1,2,3-三唑,从而获得单分子胶束。一旦达到偶联,就将叔丁酯基团在三氟乙酸中水解,并且带有羧酸作为端基的相应的树枝状大分子完全溶于pH 7.0、7.4和8.0的磷酸盐缓冲溶液