Introduction of Peripheral Carboxylates to Decrease the Charge on Tm3+ DOTAM-Alkyl Complexes: Implications for Detection Sensitivity and in Vivo Toxicity of PARACEST MRI Contrast Agents
摘要:
A series of structurally modified Tm3+ DOTAM-alkyl complexes as potential PARACEST MRI contrast agents has been synthesized with the aim to decrease the overall positive charge associated with these molecules and increase their biocompatibility. Two types of structural modification have been performed, an introduction of terminal carboxylate arms to the alkyl side chains and a conjugation of one of the alkyl side chains with aspartic acid. Detailed evaluation of the magnetic resonance imaging chemical exchange contrast associated with the structurally modified contrast agents has been performed. In contrast to the acutely toxic Tm3+ DOTAM-alkyl complexes, the structurally modified compounds were found to be tolerated well during in vivo MRI studies in mice; however, only the aspartic acid modified chelates produced an amide proton-based PARACEST signal.
Cu(I)-Catalyzed Synthesis of Dihydropyrimidin-4-ones toward the Preparation of β- and β<sup>3</sup>-Amino Acid Analogues
作者:Basker Rajagopal、Ying-Yu Chen、Chun-Chi Chen、Xuan-Yu Liu、Huei-Ren Wang、Po-Chiao Lin
DOI:10.1021/jo402670d
日期:2014.2.7
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
furnacalis (Guenée) and inhibition of this enzyme has been considered a promising strategy for the development of eco-friendly pesticides. In this article, based on the structure of the catalytic domains of OfHex1, a series of novel glycosyl triazoles were designed and synthesized via Cu-catalyzed azide-alkyne [3+2] cycloaddition reaction. To investigate the potency and selectivity of these glycosyl triazoles
A DNA‐Encoded Chemical Library Incorporating Elements of Natural Macrocycles
作者:Cedric J. Stress、Basilius Sauter、Lukas A. Schneider、Timothy Sharpe、Dennis Gillingham
DOI:10.1002/anie.201902513
日期:2019.7.8
Here we show a seven‐step chemical synthesis of a DNA‐encodedmacrocyclelibrary (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
ParaCEST MRI contrast agents capable of derivatizationvia “click” chemistry
作者:Mark Milne、Kirby Chicas、Alex Li、Robert Bartha、Robert H. E. Hudson
DOI:10.1039/c1ob06162c
日期:——
A comprehensive series of lanthanide chelates has been prepared with a tetrapropargyl DOTAM type ligand. The complexes have been characterized by a combination of 1H NMR, single-crystal X-ray crystallography, CEST and relaxation studies and have also been evaluated for potential use as paramagnetic chemical exchange saturation transfer (ParaCEST) contrast agents in magnetic resonance imaging (MRI). We demonstrate the functionalization of several chelates by means of alkyneâazide âclickâ chemistry in which a glucosyl azide is used to produce a tetra-substituted carbohydrate-decorated lanthanide complex. The carbohydrate periphery of the chelates has a potent influence on the CEST properties as described herein.
Synthesis and in vitro kinetic study of novel mono-pyridinium oximes as reactivators of organophosphorus (OP) inhibited human acetylcholinesterase (hAChE)
作者:Aditya Kapil Valiveti、Uma M. Bhalerao、Jyotiranjan Acharya、Hitendra N. Karade、Raviraju Gundapu、Anand K. Halve、Mahabir Parshad Kaushik
DOI:10.1016/j.cbi.2015.06.007
日期:2015.7
A series of mono pyridiniumoximes linked with arenylacetamides as sidechains 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