Selective monoprotection of 1,4,7,10-tetraazacyclododecane via direct reaction with 4-nitrophenyl active esters
摘要:
A simple, one-pot preparation of monoprotected 1,4,7,10-tetraazacyclododecanes via an efficient acylation reaction with 4-nitrophenyl active esters has been developed. (c) 2008 Elsevier Ltd. All rights reserved.
The present invention relates to new class of functionalized polyazamacrocycles including at least one phosphonic or phosphinic group linked to a nitrogen atom of the macrocyclic cage, and capable of chelating paramagnetic metal ions, their chelated complexes with metal ions and the use thereof as contrast agents, particularly suitable for Magnetic Resonance Imaging (MRI) analysis.
Synthesis, Relaxometric and Photophysical Properties of a New pH-Responsive MRI Contrast Agent: The Effect of Other Ligating Groups on Dissociation of a <i>p</i>-Nitrophenolic Pendant Arm
作者:Mark Woods、Garry E. Kiefer、Simon Bott、Aminta Castillo-Muzquiz、Carrie Eshelbrenner、Lydie Michaudet、Kenneth McMillan、Siva D. K. Mudigunda、Doug Ogrin、Gyula Tircsó、Shanrong Zhang、Piyu Zhao、A. Dean Sherry
DOI:10.1021/ja048299z
日期:2004.8.1
complexes. The water relaxivity of Gd(NP-DO3A) increases from 4.1 mM(-1) s(-1) at pH 9 to 7.0 mM(-1) s(-1) at pH 5 as a result of acid-catalyzed dissociation of the nitrophenol from the lanthanide. The nitrophenol group in Gd(NP-DO3AM) does not dissociate from the metal center even at pH 5; therefore, the very modest increase in relaxivity in this complex must be ascribed to an increase in prototropic
Regioselective N-substitution of cyclen with two different alkyl groups: synthesis of all possible isomersElectronic supplementary information (ESI) available: spectroscopic data. See http://www.rsc.org/suppdata/cc/b2/b212667b/
作者:Jeongsoo Yoo、David E. Reichert、Michael J. Welch
DOI:10.1039/b212667b
日期:2003.3.6
All possible configurations of two different groups on the four nitrogen atoms of cyclen were achieved using four differently protected cyclen intermediates including the novel mono-protected cyclen compound, mono-N-Cbz-cyclen.
Complete on/off responsive ParaCEST MRI contrast agents for copper and zinc
作者:K. Srivastava、G. Ferrauto、S. M. Harris、D. L. Longo、M. Botta、S. Aime、V. C. Pierre
DOI:10.1039/c8dt01172a
日期:——
Two thulium-based ParaCEST responsivecontrastagents, Tm-DOTAm-py and Tm-DOTAm-βAla-py, have been synthesized and evaluated for imaging copper and zinc. Unusual for responsiveMRIcontrastagents, both agents display a complete on/off response in the presence of transition metals. Both complexes function as paraCEST agents in the absence of copper and zinc, with the positively charged Tm-DOTAm-py
已经合成了两种基于Para的ParaCEST响应性造影剂Tm-DOTAm-py和Tm-DOTAm-βAla-py,并对其用于铜和锌的成像进行了评估。对于反应性MRI造影剂而言,这两种试剂不常见,在过渡金属存在的情况下,两种试剂均显示出完整的开/关响应。两种配合物在没有铜和锌的情况下均充当paraCEST试剂,带正电荷的Tm-DOTAm-py比带中性电荷的Tm-DOTAm-βAla-py更敏感。在每种情况下,CEST信号均来自酰胺质子,而不是来自与Tm 3+离子配位的水分子。与Cu +,Cu 2+或Zn 2+结合时,酰胺质子的交换速率大大增加,导致CEST信号完全消失。通过1 / T 1 NMRD谱,17 O NMR测量和分子模拟模拟,证实了这种有效的作用方式以及在存在和不存在过渡金属的情况下都没有内层水分子。这两种络合物都没有铜比锌具有选择性。两者都形成1:1 TmL:Cu +或2:1 TmL:Cu
Amphiphilic EuDOTA‐Tetraamide Complexes Form Micelles with Enhanced CEST Sensitivity
作者:Osasere M. Evbuomwan、Garry Kiefer、A. Dean Sherry
DOI:10.1002/ejic.201101369
日期:2012.4
equations increased in parallel with an increase in alkyl carbon chain-length. By comparisons with the monomethylamide complex, which served as control, the data illustrate that micelle formation serves to slow the rate of water exchange in these systems. The complex having the largest CEST effect per unit Eu(III) concentration (the C(16) analog) had a detection limit of 5.3 μM. This represents an approximate
报道了四种具有可变烷基链长度(C(1)、C(12)、C(14) 和 C(16))的新型 DOTA-四酰胺配体及其各自的铕 (III) 配合物的合成和表征。三个具有长烷基链的 EuL 复合物自发形成不同大小的胶束。每种复合物的临界胶束浓度不同(C(16) 复合物低于 C(12) 复合物),而胶束尺寸随着烷基链长度的增加而增加。化学交换饱和转移 (CEST) 实验表明,所有四种 Eu(III) 配合物均表现出慢至中等的水交换动力学。正如预期的那样,由于水交换速度加快,这些复合物中的 CEST 信号随着温度的升高而降低,但有趣的是,C(14) 和 C(16) 复合物的 CEST 信号在 25°C 附近达到最大值,与交换限制的 CEST 一致。或接近室温。通过将 CEST 光谱拟合到 Bloch 方程获得的水停留寿命随着烷基碳链长度的增加而增加。通过与作为对照的单甲酰胺复合物进行比较,数据表明胶束