Well-Defined Poly(lactic acid)s Containing Poly(ethylene glycol) Side Chains

Abstract

Poly(ethylene glycol) (PEG) side-chain functionalized lactide analogues have been synthesized in four steps from commercially available L-lactide. The key step in the synthesis is the 1,3-dipolar cycloaddition between PEG-azides and a highly strained spirolactide-heptene monomer, which proceeds in high conversions. The PEG-grafted lactides analogues were polymerized via ring-opening polymerization using triazacyclodecene as organocatalyst to give well-defined tri- and hepta-(ethylene glycol)-poly(lactide)s (PLA) with molecular weights above 10 kDa and polydispersity indices between 1.6 and 2.1. PEG-poly(lactide) (PLA) with PEG chain Mn 2000 was also prepared but GPC analysis showed a bimodal profile indicating the presence of starting macromonomer. Cell adhesion assays were performed using MC3T3 E-1 osteoblast-like cells demonstrating that PEG-containing PLA reduces cell adhesion significantly when compared to unfunctionalized PLA.

Long-term release of a thiobenzamide from a backbone functionalized poly(lactic acid)

“…This sequence was first reported by Hillmyer et al in 2008, and it proceeded as described in the literature. 46-48 …”

A Highly Selective and Turn‐on Fluorescent Probe for Fe3+ Ion Based on Perylene Tetracarboxylic Diimide

“…The water for spectra determination was deionized water without fluorescent impurities. Compounds 1 [15] and 3 [16] were prepared as described. All other solvents and reagents were of reagent grade and used as received.…”

“…Treatment of 1-(tert-butyloxycarbonyl)-ethyldiamine (1) [15] with propargyl bromide in the presence of K 2 CO 3 in dichloromethane afforded alkyne 2 in 90% yield. This compound then underwent a typical click reaction with azide 3, [16] which was prepared as described, in the presence of CuSO 4 •5H 2 O and sodium ascorbate to give 4 in 96% yield. Deprotection of this compound with trifluoroacetic acid (TFA) in dichloromethane produced amine 5, which was condensed with perylene-3,4:9,10-tetracarboxylic dianhydride using imidazole as a base to give probe 6 in 31% yield.…”

Methylenelactide: vinyl polymerization and spatial reactivity effects

“…MLA was first synthesized in 1969 by Scheibelhoffer et al through a bromination of L-lactide followed by a basic HBr elimination [2]. In 2008, the first Diels–Alder reaction employing MLA as dienophile was described [3–6]. In a recent NMR study we demonstrated that, poly(MLA) prepared via free radical polymerization contains mainly isotactic units.…”