A water-soluble 1,8-naphthyridine-based imidazolium molecular gripper for fluorescence sensing and discriminating of GMP
摘要:
A selective receptor for sensing and discriminating of GMP is useful not only in the energy metabolism but also in the processes of DNA replication and transcription-related to GMP; such a receptor is presently rare especially in a pure water environment. Herein, a novel 1,8-naphthyridine-based tripodal imidazolium gripper-like molecular served as a "turn-on" fluorescent receptor (TINP) was designed and synthesized for selective sensing and discriminating GMP from structurally similar GNPs (N = D and T) and XMPs (X = U, T, A, and C) in 100% aqueous solution. TINP consists of 1,8-naphthyridines and imidazolium cations. 2-acetylamino-1,8-naphthyridine was chosen as fluorophore and tri-hydrogen bonds interactions sites for the nucleobase guanine. Imida-zolium cations were identified as the phosphate part receiving moieties and communicators, while the three imidazolium cations also served as indispensable water-soluble parts. GMP caused a remarkable fluorescence enhancement (ca. 6.5-fold) with a quantum yield (Phi(f)) of 0.26 at 399 nm, displaying an efficient "turn on" behavior. The sensing mechanisms and fluorescence response were explained by Job's plot, NMR spectroscopic analysis, and theoretical calculations. The "turn-on" fluorescent property for GMP can be attributed to photoinduced electron transfer (PeT) transitions with some mixed intraligand charge-transfer (ILCT) transitions. Finally, the preliminary results of cell experiments show that the receptor can be applied for the imaging of GMP in living mammalian cells.
<i>N</i>-bromosuccinimide reactions of some heterocycles in the presence or absence of water: An overview of ring versus side chain bromination for the synthesis of important brominated heterocyclic synthons
Reactions of various heterocycles 1–6 with N-bromosuccinimide in the presence or absence of water have been studied for side chain versus ring bromination to afford some new and important heterocyclic synthons. Interestingly, the N-bromosuccinimide reaction in the presence of perchloric acid, a new condition, affords exclusively the new dibromo aminopicoline 1f, which is not obtained by other presently
Side Chain Bromination of Mono and Dimethyl Heteroaromatic and Aromatic Compounds by Solid Phase<i>N</i>-Bromosuccinimide Reaction without Radical Initiator under Microwave
A series of side chain mono and dibromo derivatives of mono and dimethyl heteroaromatic and aromatic compounds (1–17) were synthesized by one step solid phase N-bromosuccinimide (NBS) reaction with...
Naphthyridine-based symmetrical and unsymmetrical pyridinium amides in sensing of biotin salt
作者:Kumaresh Ghosh、Avik Ranjan Sarkar、Tanushree Sen
DOI:10.1080/10610270903089738
日期:2010.2.1
Two naphthyridine-based receptors have been designed and synthesised for biotin salt. The compounds serve as good hosts for the detection of biotin carboxylate rather than biotin ester. The correct dispositions of the binding groups under an isophthaloyl spacer enable the receptors to bind both the cyclic urea and the carboxylate ends simultaneously with moderate binding constant values. The receptors are effective for the binding of tetrabutylammonium salt of biotin with a concomitant increase in the fluorescence of naphthyridine and show appreciable binding of biotin salt in CH3CN containing 1.2% DMSO. The binding was monitored in CH3CN containing 1.2% DMSO and DMSO using H-1 NMR, UV-vis and fluorescence spectroscopic methods.
KELLY, T. ROSS;BRIDGER, GARY J.;ZHAO, CHEN, J. AMER. CHEM. SOC., 112,(1990) N2, C. 8024-8034