7458-03-9Relevant articles and documents
Magnetoluminescent agents for dual MRI and time-gated fluorescence imaging
Smolensky, Eric D.,Zhou, Yue,Pierre, Valerie C.
, p. 2141 - 2147 (2012)
The synthesis and properties of two luminescent iron oxide nanoparticles for dual imaging by MRI and time-gated confocal microscopy are presented. These magnetoplasmonic agents consist of macrocyclic terbium complexes conjugated onto magnetite nanoparticles by a polyethylene glycol linker. Two macrocyclic terbium complexes were investigated: Tb-DOTAm-(Phen)3 and Tb-DOTAm-(acetylene)3. Both complexes display the characteristic long luminescence lifetimes of lanthanides (0.8 ms and 1.3 ms, respectively), rendering them ideal for time-gated luminescence spectroscopy and confocal imaging - a feature currently unexplored in multimodal imaging agents. Additionally, the 5 ± 1 nm magnetite nanoparticles, with their permeable PEG coating and stable dopamide anchor, render the two constructs efficient MRI contrast agents with longitudinal (r1) and transverse (r2) relaxivities of 9.8 mM-1Fe s-1 and 98 mM -1Fe s-1 at 60 MHz and 37 °C. The synthesis and characterization of Fe3O4@Tb-DOTAm-(acetylene) 3 and Fe3O4@Tb-DOTAm-(Phen)3, two magnetoluminescent agents for dual imaging by MRI and confocal imaging are presented. The nanoparticles are characterized by high transverse and longitudinal relaxivities and long luminescence lifetimes ideal for time-gated spectroscopy. Copyright
A DNA-Encoded Chemical Library Incorporating Elements of Natural Macrocycles
Stress, Cedric J.,Sauter, Basilius,Schneider, Lukas A.,Sharpe, Timothy,Gillingham, Dennis
supporting information, p. 9570 - 9574 (2019/06/24)
Here we show a seven-step chemical synthesis of a DNA-encoded macrocycle library (DEML) on DNA. Inspired by polyketide and mixed peptide-polyketide natural products, the library was designed to incorporate rich backbone diversity. Achieving this diversity, however, comes at the cost of the custom synthesis of bifunctional building block libraries. This study outlines the importance of careful retrosynthetic design in DNA-encoded libraries, while revealing areas where new DNA synthetic methods are needed.
Direct Peptide Cyclization and One-Pot Modification Using the MeDbz Linker
Gless, Bengt H.,Olsen, Christian A.
, p. 10525 - 10534 (2018/09/06)
The one-pot synthesis and modification of cyclic peptides through a self-cleaving on-resin protocol is described. We apply Dawson's MeDbz linker to achieve direct intramolecular peptide cyclization by thioesterification followed by S → N acyl shift. This native chemical ligation approach requires no activating additive and allows direct modification of the crude cyclic peptides in one-pot. The strategy was applied to synthesize 5 cyclic peptide natural products of varying ring size. Finally, one-pot modifications include desulfurization, fluorophore conjugation, and intramolecular disulfide formation.
Synthesis of gibberellic acid derivatives and their effects on plant growth
Tian, Hao,Xu, Yiren,Liu, Shaojin,Jin, Dingsha,Zhang, Jianjun,Duan, Liusheng,Tan, Weiming
supporting information, (2017/06/08)
A series of novel C-3-OH substituted gibberellin derivatives bearing an amide group were designed and synthesized from the natural product gibberellic acid (GA3). Their activities on the plant growth regulation of rice and Arabidopsis were evaluated in vivo. Among these compounds, 10d and 10f exhibited appreciable inhibitory activities on rice (48.6% at 100 μmol/L) and Arabidopsis (41.4% at 100mol/L), respectively. These results provide new insights into the design and synthesis of potential plant growth regulators.
Optimizing the readout of lanthanide-DOTA complexes for the detection of ligand-bound copper(I)
Hanna, Jill R.,Allan, Christopher,Lawrence, Charlotte,Meyer, Odile,Wilson, Neil D.,Hulme, Alison N.
supporting information, (2017/06/08)
The CuAAC 'click' reaction was used to couple alkyne-functionalized lanthanide-DOTA complexes to a range of fluorescent antennae. Screening of the antenna components was aided by comparison of the luminescent output of the resultant sensors using data normalized to account for reaction conversion as assessed by IR. A maximum 82-fold enhanced signal:background luminescence output was achieved using a Eu(III)-DOTA complex coupled to a coumarin-azide, in a reaction which is specific to the presence of copper(I). This optimized complex provides a new lead design for lanthanide-DOTA complexes which can act as irreversible 'turn-on' catalytic sensors for the detection of ligand-bound copper(I).
Synthesis and antimalarial activity of N-benzylated (N-arylcarbamoyl)alkylphosphonic acid derivatives
Adeyemi, Christiana M.,Faridoon,Isaacs, Michelle,Mnkandhla, Dumisani,Hoppe, Heinrich C.,Krause, Rui W.M.,Kaye, Perry T.
, p. 6131 - 6138 (2016/12/06)
A series of novel and readily accessible N-benzylated (N-arylcarbamoyl)alkylphosphonate esters and related compounds have been prepared as potential antimalarial agents. Bioassays reveal that some of these compounds exhibit promising activity against Plasmodium falciparum, and exhibit no significant growth inhibition of HeLa cells.
Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD of Pseudomonas aeruginosa
Prothiwa, Michaela,Szamosvári, Dávid,Glasmacher, Sandra,B?ttcher, Thomas
supporting information, p. 2784 - 2792 (2017/01/09)
The human pathogen Pseudomonas aeruginosa uses the pqs quorum sensing system to coordinate the production of its broad spectrum of virulence factors to facilitate colonization and infection of its host. Hereby, the enzyme PqsD is a virulence related quoru
Synthesis and in vitro kinetic study of novel mono-pyridinium oximes as reactivators of organophosphorus (OP) inhibited human acetylcholinesterase (hAChE)
Valiveti, Aditya Kapil,Bhalerao, Uma M.,Acharya, Jyotiranjan,Karade, Hitendra N.,Gundapu, Raviraju,Halve, Anand K.,Kaushik, Mahabir Parshad
, p. 125 - 132 (2015/06/25)
A series of mono pyridinium oximes linked with arenylacetamides as side chains were synthesized and their in vitro reactivation potential was evaluated against human acetylcholinesterase (hAChE) inhibited by organophosphorus inhibitors (OP) such as sarin, VX and tabun. The reactivation data of the synthesized compounds were compared with those obtained with standard reactivators such as 2-PAM and obidoxime. The dissociation constant (KD) and specific reactivity (kr) of the oximes were also determined by performing reactivation kinetics against OP inhibited hAChE. Among the synthesized compounds, oximes 1-(2-(4-cyanophenylamino)-2-oxoethyl)-4-((hydroxyimino)methyl)pyridinium chloride (12a) and 4-((hydroxyimino)methyl)-1-(2-(4-methoxyphenylamino)-2-oxoethyl)pyridinium chloride (2a) were found most potent reactivators for hAChE inhibited by sarin. In case of VX inhibited hAChE majority of the oximes have shown good reactivation efficacies. Among these oximes 1-(2-(benzylamino)-2-oxoethyl)-4-((hydroxyimino)methyl)pyridinium chloride (18a), 4-((hydroxyimino)methyl)-1-(2-(4-(methoxycarbonyl)phenylamino)-2-oxoethyl)pyridinium-chloride (14a) and 12a were found to surpass the reactivation potential of 2-PAM and obidoxime. However, the synthesized oximes showed marginal reactivation efficacies in case of tabun inhibited hAChE. The pKa value of the oximes were determined and correlated with their observed reactivation potential.
Consecutive three-component synthesis of (hetero)arylated propargyl amides by chemoenzymatic aminolysis-Sonogashira coupling sequence
Hassan, Sidra,Ullrich, Anja,Müller, Thomas J. J.
supporting information, p. 1571 - 1576 (2015/01/30)
A novel chemoenzymatic three-component synthesis of (hetero)arylated propargyl amides in good yields based upon Novozyme 435 (Candida antarctica lipase B (CAL-B)) catalyzed aminolysis of methyl carboxylates followed by Sonogashira coupling with (hetero)aryliodides in a consecutive one-pot fashion has been presented. This efficient methodology can be readily concatenated with a CuAAC (Cu catalyzed alkyne azide cycloaddition) as a third consecutive step to furnish 1,4-disubstituted 1,2,3-triazole ligated arylated propargyl amides. This one-pot process can be regarded as a transition metal catalyzed sequence that takes advantage of the copper source still present from the cross-coupling step.
Cu(I)-catalyzed synthesis of dihydropyrimidin-4-ones toward the preparation of β- And β3-amino acid analogues
Rajagopal, Basker,Chen, Ying-Yu,Chen, Chun-Chi,Liu, Xuan-Yu,Wang, Huei-Ren,Lin, Po-Chiao
supporting information, p. 1254 - 1264 (2014/03/21)
A copper(I)-catalyzed synthesis of substituted dihydropyrimidin-4-ones from propargyl amides via the formation of ketenimine intermediate has been successfully developed; the synthesis afforded good isolated yields (80-95%). The mild reaction conditions at room temperature allow the reaction to proceed to completion in a few hours without altering the stereochemistry. Further, by involving a variety of reactive nucleophiles, the obtained substituted dihydropyrimidin-4-ones were elegantly transformed into the corresponding β- and β3-amino acid analogues.