The Synthesis And Supramolecular Chemical Properties Of New Macrocyclic Compounds Based On Hemicucurbit[n]uril

Cucurbituril,is a macrocyclic cavitand that is made of glycoluril molecules,and formaldehyde units.Although it has been known since 1905,it was first characterized by Mock and co-workers in 1981.A few substituted cucurbiturils and homologues have also been prepared and characterized,all having a hydrophobic cavity that is accessible through two identical carbonyl-fringed portals.The rigid structure and the combination of a hydrophobic cavity with polar portals allow these cavitands to host various molecules and cations,rendering the CBs attractive synthetic receptors and useful building blocks of various supramolecular structures.Hemicucurbituril was firstly synthesized by Miyahara in 2004.Hemicucurbituril is exactly one half of cucurbituril cutting along the molecular equator.The hemicucurbituril have the alternating orientation of carbonyl groups,The initial expectations were that the supramolecular binding properties of the hemicucurbiturils are expected to resemble to those of the cucurbiturils,but this was quickly proved wrong,mainly because of the contradistinctive structural features of the two types of macrocycles.The original hemicucurbit[n]urils suffer from sparse solubility,which limits their applications in supramolecular chemistry.A series of functionalized hemicucurbit[n]uril derivatives have been prepared and studied.In this paper,the carbonyl group that affects hemicucurbituril is modified to prepare a series of thio-hemicucurbituril,and the supramolecular chemical properties are preliminarily explored.The main research contents are as follows:(1)Synthesis of thio-hemicucurbituril:The synthesis of thio-hemicucurbituril at a specific location was investigated.The synthesis of mono-thio-hemicucurbituril was carried out in the way of synthesis of hemicucurbituril.The amount of ethylenethiourea far exceeds that of ethyleneurea,finally,mono-thiohemicucurbituril was synthesized with higher yield.A series of thioheterofragments were constructed for the para-dithio-hemicucurbituril and the meta-trithio-hemicucurbit,and the thio-hemicucurbituril were successfully synthesized.(2)Preliminary supramolecular chemical properties of the synthesized thio-hemeicucurbituril were studied:the interaction with catechol was investigated by~1HNMR spectra,isothermal titration thermal analysis(ITC),and it was found that the thio-hemocucurbituril carbonyl oxygen could interact with the hydroxyl group of catechol through hydrogen bond,The hydrogen bond interaction is relatively weak.Thio-hemicucurbituril are selective.(3)We have developed a simple way to synthesize sulfonylguanidines from tetra-substituted urines with good yields,which provides a convenient method for synthesis of sulfonyl group protected guanidine in one step.During this process,we are getting familiar with the synthesis and properties of the azasemiglucuron derivatives,which laid the foundation for the subsequent synthesis of aza-hemicucurbituril.