- In-chain functionalization through the combination of ring opening copolymerization and oxime “Click” reaction towards X-ray opaque polylactide copolymers
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X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications. In this work, a strategy of in-chain functionalization through the combination of ring opening copolymerization and oxime “Click” postfunctionalization was developed towards X-ray opaque polylactide copolymers. A functionalized cyclic carbonate was first synthesized and used as comonomer of polylactide copolymers, which were subjected to postfunctionalization of oxime “Click” reaction towards iodinated polylactide copolymers. The chemical structure and physical properties of the target products were traced and confirmed. In vitro cytotoxicity evaluation with 3T3-Swiss albino by Alamar blue demonstrated a low cytotoxicity. The X-ray radiopacity was analyzed by Micro-CT and quantified by Hounsfield Units value, which could be tailorable by the feedstock. It is a promising X-ray visible implantable biomaterial in biomedical applications.
- Wang, Wenhuan,Sang, Lin,Kong, Weizong,Zhao, Yiping,Wei, Zhiyong,Li, Yang
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supporting information
p. 551 - 553
(2019/05/07)
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- Synthesis of 6-membered cyclic carbonates from 1,3-diols and low CO2 pressure: A novel mild strategy to replace phosgene reagents
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Low pressure carbon dioxide is used as the carbonation agent in a simple, safe and efficient procedure for the synthesis of 6-membered cyclic carbonates from 1,3-diols. Using readily available reagents and proceeding at room temperature, this route offers a novel mild alternative to phosgene derivatives.
- Gregory, Georgina L.,Ulmann, Marion,Buchard, Antoine
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p. 39404 - 39408
(2015/05/20)
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- Semicrystalline dihydroxyacetone copolymers derived from glycerol
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The ring-opening polymerization of glycerol-derived six-membered cyclic dimethylacetal dihydroxyacetone carbonate (MeO2DHAC) have been studied both in solution and bulk conditions with organic catalysts. The guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was the most active catalyst in solution, whereas the thiourea/sparteine catalytic system displayed the most predictable kinetics. Ring-opening polymerization of MeO2DHAC or copolymerization with ε-caprolactone (CL) in the melt occurred readily with TBD as catalyst to afford random copolymers. Acetal deprotection afforded the polycarbonate poly(dihydroxyactone carbonate) (p(DHAC)) or poly(carbonate ester) copolymers p(DHAC-r-CL). The polycarbonate p(DHAC) is a high-melting thermoplastic with a melting point of 246 °C. The p(DHAC-r-CL) copolymers all displayed semicrystalline behavior as evidenced by DSC and WAXS analysis with Tg and Tm changing as a function of comonomer composition. These new materials could have potential use in biomedical applications or as biomass-derived thermoplastics.
- Simon, Jeff,Olsson, Johan V.,Kim, Hyunuk,Tenney, Ian F.,Waymouth, Robert M.
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p. 9275 - 9281
(2013/02/25)
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- Poly(carbonate-ester)s of dihydroxyacetone and lactic acid as potential biomaterials
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The synthesis of new polymeric biomaterials using biocompatible building blocks is important for the advancement of the biomedical field. We report the synthesis of statistically random poly(carbonate-ester)s derived from lactic acid and dihydroxyacetone by ring-opening polymerization. The monomer mole feed ratio and initiator concentration were adjusted to create various copolymer ratios and molecular weights. A dimethoxy acetal protecting group was used to stabilize the dihydroxyacetone and was removed using elemental iodine and acetone at reflux to produce the final poly(lactide-co-dihydroxyacetone) copolymers. The characteristics of the copolymers in their protected and deprotected forms were characterized by 1H NMR, 13C NMR, GPC, TGA, and DSC. Hydrolytic degradation of the deprotected copolymers was tracked over an 8-week time frame. The results show that faster degradation occurred with increased carbonate content in the copolymer backbone. The degradation pattern of the copolymers was visualized using SEM and revealed a trend toward surface erosion as the primary mode of degradation.
- Weiser, Jennifer R.,Zawaneh, Peter N.,Putnam, David
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experimental part
p. 977 - 986
(2012/03/08)
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- Palladium-catalyzed carbonylation of diols to cyclic carbonates
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The catalytic alkoxycarbonylation of 1,2-diols by (neocuproine) palladium(II) acetate (neocuproine=2,9-dimethyl-1,10-phenanthroline) or palladium(II) acetate/(-)-sparteine using N-chlorosuccinimide as the oxidant affords cyclic carbonates. The oxidative carbonylation of diols proceeds under mild conditions, requiring only 1 atm of carbon monoxide, and produces cyclic carbonates in moderate to good yields. Both 1,2- and 1,3-diols can be carbonylated using (neocuproine)Pd(OAc)2 and sodium dichloroisocyanuric acid, which serves as a competent oxidant and base for this system, to yield 5- and 6-membered cyclic carbonates. Copyright
- Pearson, David M.,Conley, Nicholas R.,Waymouth, Robert M.
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supporting information; experimental part
p. 3007 - 3013
(2011/12/16)
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