Development of New 1,3-Diazaphenoxazine Derivatives (ThioG-Grasp) to Covalently Capture 8-Thioguanosine

The derivatives of 8-thioguanosine are thought to be included in the signal transduction system related to 8-nitroguanosine. In this study, we attempted to develop new 1,3-diazaphenoxazine (G-clamp) derivatives to covalently capture 8-thioguanosine (thioG-grasp). It was expected that the chlorine atom at the end of the linker would be displaced by the nucleophilic attack by the sulfur atom of 8-thioguanosine via multiple hydrogen-bonded complexes. The thioG-grasp derivative with a propyl linker reacted efficiently with 8-thioguanosine to form the corresponding adduct

Efficient Covalent Capture of 8‑Nitroguanosine <i>via</i> a Multiple Hydrogen-Bonded Complex

A novel 1,3-diazaphenoxazine nucleoside derivative (nitroG-Grasp) bearing a thiol group with a urea linker forms multiple hydrogen-bonded complexes with 8-nitroguanosine and efficiently displaces the nitro group; thus, it is the first molecule that can covalently capture 8-nitroguanosine

Effect of Hydrophobicity on the Self-Assembly Behavior of Urea Benzene Derivatives in Aqueous Solution

Urea benzene derivatives (UBD) with amphiphilic side chains showed self-assembly behavior in aqueous solution to form nanoparticles ~100 nm in size. Subsequent thermal treatment led to additional self-assembly of the nanoparticles due to dehydration of the amphiphilic side chains, producing microparticles. This self-assembly process was accompanied by a lower critical solution temperature (LCST) behavior, as revealed by the abrupt decrease in solution transmittance. In this study, three UBD (UBD-1&ndash;3) with different lengths of the alkyl segment in the amphiphilic side chain (namely, hexyl, heptyl, and octyl, respectively) were prepared to investigate the self-assembly behavior in aqueous solution. UBD-1&ndash;3 formed identical nanoparticles, with sizes in the 10~80 nm range but with different LCST values in the order 3 &lt; 2 &lt; 1. These results suggest a relationship between the hydrophobicity and the self-assembly behavior of UBD

Fluorescence Tumor-Imaging Using a Thermo-Responsive Molecule with an Emissive Aminoquinoline Derivative

We synthesized (2,4-trifluoromethyl-7-N-bis(2,5,8,11-tetraoxatridecane-13-yl)-aminoquinoline) TFMAQ-diEg4, an emissive aminoquinoline derivative that incorporated two tetraethyleneglycol chains into an amino group. TFMAQ-diEg4 showed fluorescence and thermo-responsive properties accompanied by a lower critical solution temperature (LCST), due to the introduction of the oligoethylene glycol chain. This thermo-responsive LCST behavior occurred at the border of a cloud point. Below and above the cloud point, self-assemblies of 6-7-nm nanoparticles and ~2000-nm microparticles were observed, in vitro. In addition, TFMAQ-diEg4 showed a high solubility, over 20 mM for aqueous solution, in vivo, which not only prevented thrombosis but also allowed various examinations, such as single intravenous administration and intravenous drips. Intravenous administration of TFMAQ-diEg4, to tumor-bearing, mice led to the accumulation of the molecule in the tumor tissue, as observed by fluorescence imaging. A subset of mice was treated with local heat around their tumor tissue and an intravenous drip of TFMAQ-diEg4, which led to a high intensity of TFMAQ-diEg4 emission within the tumor tissue. Therefore, we revealed that TFMAQ-diEg4 was useful as a fluorescence probe with thermo-responsive properties

Fluorescence Tumor-Imaging Using a Thermo-Responsive Molecule with an Emissive Aminoquinoline Derivative.

We synthesized (2,4-trifluoromethyl-7--bis(2,5,8,11-tetraoxatridecane-13-yl)-aminoquinoline) TFMAQ-diEg4, an emissive aminoquinoline derivative that incorporated two tetraethyleneglycol chains into an amino group. TFMAQ-diEg4 showed fluorescence and thermo-responsive properties accompanied by a lower critical solution temperature (LCST), due to the introduction of the oligoethylene glycol chain. This thermo-responsive LCST behavior occurred at the border of a cloud point. Below and above the cloud point, self-assemblies of 6-7-nm nanoparticles and ~2000-nm microparticles were observed, in vitro. In addition, TFMAQ-diEg4 showed a high solubility, over 20 mM for aqueous solution, in vivo, which not only prevented thrombosis but also allowed various examinations, such as single intravenous administration and intravenous drips. Intravenous administration of TFMAQ-diEg4, to tumor-bearing, mice led to the accumulation of the molecule in the tumor tissue, as observed by fluorescence imaging. A subset of mice was treated with local heat around their tumor tissue and an intravenous drip of TFMAQ-diEg4, which led to a high intensity of TFMAQ-diEg4 emission within the tumor tissue. Therefore, we revealed that TFMAQ-diEg4 was useful as a fluorescence probe with thermo-responsive properties