4443-26-9Relevant articles and documents
General protocol for the synthesis of functionalized magnetic nanoparticles for magnetic resonance imaging from protected metal-organic precursors
Hu, He,Zhang, Chongkun,An, Lu,Yu, Yanrong,Yang, Hong,Sun, Jin,Wu, Huixia,Yang, Shiping
, p. 7160 - 7167 (2014)
The development of magnetic nanoparticles (MNPs) with functional groups has been intensively pursued in recent years. Herein, a simple, versatile, and cost-effective strategy to synthesize water-soluble and amino-functionalized MNPs, based on the thermal decomposition of phthalimide-protected metal-organic precursors followed by deprotection, was developed. The resulting amino-functionalized Fe3O4, MnFe2O4, and Mn3O4 MNPs with particle sizes of about 14.3, 7.5, and 6.6 nm, respectively, had narrow size distributions and good dispersibility in water. These MNPs also exhibited high magnetism and relaxivities of r 2=107.25 mM-1 s-1 for Fe3O 4, r2=245.75 mM-1 s-1 for MnFe 2O4, and r1=2.74 mM-1 s-1 for Mn3O4. The amino-functionalized MNPs were further conjugated with a fluorescent dye (rhodamine B) and a targeting ligand (folic acid: FA) and used as multifunctional probes. Magnetic resonance imaging and flow-cytometric studies showed that these probes could specifically target cancer cells overexpressing FA receptors. This new protocol opens a new way for the synthesis and design of water-soluble and amino-functionalized MNPs by an easy and versatile route.
Live-Cell Protein Modification by Boronate-Assisted Hydroxamic Acid Catalysis
Adamson, Christopher,Kajino, Hidetoshi,Kanai, Motomu,Kawashima, Shigehiro A.,Yamatsugu, Kenzo
, p. 14976 - 14980 (2021/09/29)
Selective methods for introducing protein post-translational modifications (PTMs) within living cells have proven valuable for interrogating their biological function. In contrast to enzymatic methods, abiotic catalysis should offer access to diverse and new-to-nature PTMs. Herein, we report the boronate-assisted hydroxamic acid (BAHA) catalyst system, which comprises a protein ligand, a hydroxamic acid Lewis base, and a diol moiety. In concert with a boronic acid-bearing acyl donor, our catalyst leverages a local molarity effect to promote acyl transfer to a target lysine residue. Our catalyst system employs micromolar reagent concentrations and affords minimal off-target protein reactivity. Critically, BAHA is resistant to glutathione, a metabolite which has hampered many efforts toward abiotic chemistry within living cells. To showcase this methodology, we installed a variety of acyl groups inE. colidihydrofolate reductase expressed within human cells. Our results further establish the well-known boronic acid-diol complexation as abona fidebio-orthogonal reaction with applications in chemical biology and in-cell catalysis.
Oxidative damage of proline residues by nitrate radicals (NO3): A kinetic and product study
Nathanael, Joses G.,Nuske, Madison R.,Richter, Annika,White, Jonathan M.,Wille, Uta
, p. 6949 - 6957 (2020/10/02)
Tertiary amides, such as in N-acylated proline or N-methyl glycine residues, react rapidly with nitrate radicals (NO3) with absolute rate coefficients in the range of 4-7 × 108 M-1 s-1 in acetonitrile. The major pathway proceeds through oxidative electron transfer (ET) at nitrogen, whereas hydrogen abstraction is only a minor contributor under these conditions. However, steric hindrance at the amide, for example by alkyl side chains at the α-carbon, lowers the rate coefficient by up to 75%, indicating that NO3-induced oxidation of amide bonds proceeds through initial formation of a charge transfer complex. Furthermore, the rate of oxidative damage of proline and N-methyl glycine is significantly influenced by its position in a peptide. Thus, neighbouring peptide bonds, particularly in the N-direction, reduce the electron density at the tertiary amide, which slows down the rate of ET by up to one order of magnitude. The results from these model studies suggest that the susceptibility of proline residues in peptides to radical-induced oxidative damage should be considerably reduced, compared with the single amino acid.
Assembling of medium/long chain-based β-arylated unnatural amino acid derivatives via the Pd(II)-catalyzed sp3 β-C-H arylation and a short route for rolipram-type derivatives
Tomar, Radha,Bhattacharya, Debabrata,Babu, Srinivasarao Arulananda
, p. 2447 - 2465 (2019/03/26)
In this paper, we report the assembling of libraries of β-arylated short/medium/long chain-based non-α-amino acid (aminoalkanoic acid) derivatives via the Pd(II)-catalyzed, bidentate directing group 8-aminoquinoline-aided sp3 β-C-H activation/arylation method. Short/medium chain-based unnatural amino acid derivatives containing an aryl group at the β-position are promising small molecules with therapeutic properties. Thus, it is necessary to enrich the libraries of short/medium/long chain-based unnatural amino acid derivatives containing an aryl group at the β-position. Considering the importance of β-arylated short/medium/long chain-based non-α-amino acid derivatives, an inclusive attention was paid to explore the Pd(II)-catalyzed sp3 β-C-H arylation of short/medium/long chain-based non-α-amino acids. Representative synthetic transformations including a short route for the assembling of rolipram and related compounds and 3-arylated GABA derivatives such as, baclofen, phenibut and tolibut were shown using selected β-C-H arylated non-α-amino acid derivatives.
