Modular design of glyco-microspheres via mild pericyclic reactions and their quantitative analysis

Abstract

The facile and efficient functionalization of porous poly(glycidyl methacrylate) (pGMA) microspheres via hetero Diels-Alder (HDA) chemistry with poly(3-O-acryloyl-1,2:5,6-di-O-isopropylidene-a-Dglucofuranoside) (pAIpGlc) prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization employing electron deficient thiocarbonylthio compounds (benzyl pyridin-2yldithioformate (BPDF)) is described in detail. The efficiency of the employed 'grafting to' approach is qualitatively and quantitatively analyzed. Initially the microspheres are functionalized with a highly reactive diene -cyclopentadiene (Cp) -in one step with sodium cyclopentadienide, and subsequently reacted with a protected glycopolymer (number-average molecular weight, M n ¼ 4200 g mol À1 ; polydispersity index, PDI ¼ 1.2) that carries a thiocarbonyl moiety functioning as a dienophile. The functionalization of the microspheres is achieved under mild conditions (T ¼ 50 C) with trifluoroacetic acid (TFA) as a readily removable catalyst. Deprotection of the grafted pAIpGlc to poly(3-O-acryloyla,b-D-glucopyranoside) (pAGlc) can be performed after functionalization in one pot with formic acid at ambient temperature. The obtained loading capacity is 2.63 Â 10 19 chains per g and the grafting density is close to 0.16 chains per nm 2 . Quantitative analysis of the grafting densities is achieved via elemental analysis; the pore size distribution before functionalization was analyzed by inverse size exclusion chromatography (iSEC). Further employed characterization techniques include scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and high resolution attenuated total reflectance (ATR) FT-IR microscopy supporting the successful modification of the microspheres.

Investigation of the thermal properties of glycidyl methacrylate–ethylene glycol dimethacrylate copolymeric microspheres modified by Diels–Alder reaction

“…As it was described earlier [23,24], the epoxide group is able to react with sodium cyclopentadienide, and after that cyclopentadienyl moiety is attached to the surface of microspheres named as poly(GMA-co-EGDMA)-Cp. Afterwards, the Diels-Alder reaction of Cp-functionalized microspheres with maleic anhydride was performed and poly(GMA-co-EGDMA)-MA material was obtained.…”

“…1. Firstly, the reaction with sodium cyclopentadienide (NaCp) was carried out [23,24]. Generally, the reaction was performed at about -7°C, in dry THF, using the twofold molar excess of NaCp relative to the number of epoxide groups in the polymer matrix.…”

Synthesis of Glycopolymer Architectures by Reversible-Deactivation Radical Polymerization

“…The same group [185] described the decoration of poly(glycidyl methacrylate) microspheres with glycopolymer chains by HDA addition. Thus, glucofuranose acrylate M9 was polymerized using dithioester RAFT agent R23 (toluene, 75 C) to obtain a fairly uniform polymer with M n = 4200 Da and Ð = 1.20 (p = 25%, Entry 209, Table 3).…”

Access to Intrinsically Glucoside‐Based Microspheres with Boron Affinity

“…Glucoside‐based microspheres are commonly achieved by utilizing a template microsphere employing either a grafting‐from approach with glycomonomers,14–17 or a grafting‐to approach with single sugars1, 18 or glycopolymers 1, 19. Although many efficient grafting‐to techniques for microspheres have become mainstream,20 it is unarguably advantageous to achieve microspheres inherently containing the desired functionality.…”