- Synthesis, Radiolabeling, and in Vivo Imaging of PEGylated High-Generation Polyester Dendrimers
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A fifth generation aliphatic polyester dendrimer was functionalized with vinyl groups at the periphery and a dipicolylamine Tc(I) chelate at the core. This structure was PEGylated with three different molecular weight mPEGs (mPEG160, mPEG350, and mPEG750) using thiol-ene click chemistry. The size of the resulting macromolecules was evaluated using dynamic light scattering, and it was found that the dendrimer functionalized with mPEG750 was molecularly dispersed in water, exhibiting a hydrodynamic diameter of 9.2 ± 2.1 nm. This PEGylated dendrimer was subsequently radiolabeled using [99mTc(CO)3(H2O)3]+ and purified to high (>99%) radiochemical purity. Imaging studies were initially performed on healthy rats to allow comparison to previous Tc-labeled dendrimers and then on xenograft murine tumor models, which collectively showed that the dendrimers circulated in the blood for an extended period of time (up to 24 h). Furthermore, the radiolabeled dendrimer accumulated in H520 xenograft tumors, which could be visualized by single-photon emission computed tomography (SPECT). The reported PEGylated aliphatic polyester dendrimers represent a new platform for developing tumor-targeted molecular imaging probes and therapeutics.
- McNelles, Stuart A.,Knight, Spencer D.,Janzen, Nancy,Valliant, John F.,Adronov, Alex
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- Light-enabled synthesis of anhydrides and amides
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Recently, we have demonstrated that the photogeneration of Vilsmeier-Haack reagents is possible using only dimethylformamide (DMF) and tetrabromomethane (CBr4) in the bromination of alcohols. Extending these findings to carboxylic acid substrates has produced a mild and facile approach to the in situ formation of symmetric anhydrides, which were conveniently converted to amide derivatives in a one-pot process. The efficient protocols discussed herein are marked by use of UVA LEDs (365 nm), which have reduced the reaction times and come with a low setup cost.
- Mccallum, Terry,Barriault, Louis
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p. 2874 - 2878
(2015/03/30)
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- N-Hydroxy and N-acyloxy peptides: Synthesis and chemical modifications
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The preparation of a series of N-hydroxy peptides is described, along with their acylation on the oxygen of the pseudopeptide bond. Nineteen N-acyloxy peptides, first examples of this new class of pseudopeptides, were thus synthesized; they present a range of acyl groups, including N-protected amino acyl groups. Possibilities of elongation for these pseudopeptides were also investigated. The Royal Society of Chemistry 2006.
- Lawrence, James,Cointeaux, Laure,Maire, Pascal,Vallee, Yannick,Blandin, Veronique
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p. 3125 - 3141
(2008/03/12)
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- The Pent-4-enoyl Group: A Novel Amine-Protecting Group That Is Readily Cleaved under Mild Conditions
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Primary and secondary amines are readily protected as N-pent-4-enoyl derivatives, the resulting N-pent-4-enamides being usually highly crystalline.Deprotection is rapidly and efficiently effected under mild conditions by treatment with 3 equiv of iodine in aqueous THF solution.Although an oxidizing medium, these deprotection conditions do not affect oxidizable functionalities including p-methoxybenzyl ethers and alkyl sulfides.
- Madsen, Robert,Roberts, Carmichael,Fraser-Reid, Bert
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p. 7920 - 7926
(2007/10/03)
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- 2-(Trimethylsilyl)ethyl glycosides. Transformation into the corresponding 1-O-acyl sugars.
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(Trimethylsilyl)ethyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside and (trimethylsilyl)ethyl 2,3,6-tri-O-acetyl-4-O-(2,3,6-tri-O-acetyl-4-O-[2-acetamido-4,6-di-O-ace tyl-2- deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D- galactopyranos
- Ellervik,Magnusson
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p. 826 - 828
(2007/10/02)
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