Agrahari Anand K, Singh Anoop S, Mukherjee Rishav, Tiwari Vinod K
Department of Chemistry, Centre of Advanced Study, Institute of Science, Banaras Hindu University Varanasi-221005 India
RSC Adv. 2020 Aug 26;10(52):31553-31562. doi: 10.1039/d0ra05289b. eCollection 2020 Aug 21.
The primary motive behind this article is to bring to the forefront a unique kind of dendrimer which has remained a dark horse since its discovery, namely dentromer. We herein report the synthesis of glycodendrimers and glycodentromers crowned with galactose units by harnessing an expeditious synthesis of dendrimer core 18 and dentromer core 19, divergently with branching directionality (1 → 2) and (1 → 3), respectively. A competent, double stage convergent synthetic path was chosen to facilitate ease of refining and spectroscopic elucidations. By exploiting a Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction strategy, we successfully developed a new series of galactosylated dendrimers 20, 21, 22, and 24 containing 6, 12, 18, and 18 peripheral galactose units, respectively. We are first to report the practical synthesis of 9-peripheral galactose coated glycodentromer 23 (0 generation) and 27-peripheral galactose coated glycodentromer 25 (1 generation). These synthesized scaffolds were characterized by spectral studies such as H, C NMR, FT-IR, MALDI-TOF MS, HRMS and SEC analysis. Additionally, gel permeation chromatography depicted the regular progression in size from 6 to 27-peripheral galactose coated glycodendrimers along with glycodentromers, with their high monodispersity. Also, the glyco-dendrimers and dentromers synthesized from two different hypercore units dendrimers core (18) and dentromer core (19), have been supported by their UV-visible absorbance and emission spectroscopy.
本文的主要目的是将一种自发现以来一直不为人知的独特树枝状大分子——牙本质单体(dentromer)呈现在大家面前。我们在此报告了通过快速合成树枝状大分子核心18和牙本质单体核心19,分别以(1→2)和(1→3)的分支方向发散合成冠有半乳糖单元的糖基树枝状大分子和糖基牙本质单体。选择了一条高效的双阶段收敛合成路径,以方便提纯和光谱解析。通过利用铜(I)催化的叠氮化物-炔烃环加成(CuAAC)反应策略,我们成功开发了一系列新的半乳糖基化树枝状大分子20、21、22和24,它们分别含有6、12、18和18个外围半乳糖单元。我们首次报道了9个外围半乳糖包覆的糖基牙本质单体23(0代)和27个外围半乳糖包覆的糖基牙本质单体25(1代)的实际合成。这些合成的支架通过诸如氢、碳核磁共振、傅里叶变换红外光谱、基质辅助激光解吸电离飞行时间质谱、高分辨质谱和尺寸排阻色谱分析等光谱研究进行了表征。此外,凝胶渗透色谱显示了从6个到27个外围半乳糖包覆的糖基树枝状大分子以及糖基牙本质单体在尺寸上的规律变化,且具有高单分散性。而且,由两种不同的超核心单元——树枝状大分子核心(18)和牙本质单体核心(19)合成的糖基树枝状大分子和牙本质单体,通过紫外可见吸收光谱和发射光谱得到了验证。