Synthesis, Characterization And Conformational Control Of Oligomer Based On Pyrrole Amide Skeletons

Stimuli-responsive conformational control of biomacromolecules is key to their chemical and biological functions.In supramolecular chemistry,a number of artificial compounds has been established in recent years to mimic such responsive systems which have high affinities and exquisite selectivities.Insight that response process of thesesystemscangiveintothefundamentalsofsupramolecular recognition—especially those in physiological environments.Such as protein folding,membrane transport,viral entry and translocation.Most examples show the conformational control relies on the host-guest interaction,espectially by hydrogen binding.These artificial oligomers are usually made of aromatic heterocycles bearing hydrogen donor and acceptor bonding sites.Pyrrole,a five-membered aromatic heterocyclic compound,is an important subunit for many macrocycles in living systems.Artificial pyrrole-based compounds have been synthesized as useful agents for recognision carbohydrates,anions,and even DNA.In addition,the researchers also combined pyrrole with heterocyclic compounds(such as pyridine,thiophene and quinoline)to prepare linear or cyclic oligomers with more recognition sites to identify different guests.However,no report is available on the study of conformational control to pyrrole-based oligoamide compounds.In this thesis,a new type of pyrrole-based oligoamide compound have been designed,synthesized,and characterized.The details are as follows:1.Mainly focuses on the background of this study,the development status of stimuli-responsive compounds and anion recognition systems based on pyrrole derivatives was reviewed.Finally,the research idea of this paper is put forward.2.Design and synthesis of pyrrole oligoamides.Pyrrol dimer was synthesized by convergent method with 1H-pyrrole as the main component.The desired pentamer was successfully achieved in moderate yield by the coupling reaction between mono-diacid chloride and further modified pyrrole dimer amine.3.Structure and conformational control of pyrrole-based oligoamides.Single crystal X-ray diffraction and 2D NMR experiments show pyrrole-based oligoamide adopts two main conformations.We used ~1H NMR titration technique to screen the anion guest with the best binding ability to pyrrole pentamer,and the equivalent concentration required for 2D NMR experiments was screened too.Then 2D NMR experiments proved that the conformation of pyrrole pentamer can be sorted out and stabilized via host-guest binding recognition of a dihydrogen phosphate anion.