Tetraethylene Glycol Moieties Research Articles

A clickable folic acid-rhamnose conjugate for selective binding to cancer cells

Specific cell surface receptors present in abundance on tumor cells have been used for targeted therapies of antibodies. Antibody based therapies involving antibody recruiting molecules (ARM) for treatment of cancer are selective and have low occurrence of side effects. The therapeutic potential of these therapies can be made more efficient by utilizing endogenously present antibodies in human serum. Herein we designed, synthesized and evaluated the potential of a novel ARM having folic acid as a targeting ligand and l-rhamnose as antibody recruiting molecule, linked via a tetraethylene glycol moiety. Exposure of tumor cells to the conjugate resulted in efficient and cell specific binding which was observed using alkyne as a reporter through click chemistry.

The synthesis and purification of amphiphilic conjugated donor–acceptor block copolymers

Nanoscale domains of donor and acceptor materials are crucial for charge generation in organic photovoltaic devices. These domains are difficult to achieve reproducibly in blended materials, but could be engineered into single-material active layers composed of donor–acceptor block copolymers (BCPs). In this work, we report the synthesis and purification of two novel fully conjugated BCPs, P3HT-b-PFTEGTBT and P3HT-b-PFTEGT6BT. To enhance phase separation and self-assembly, these two polymers incorporate tetraethylene glycol side chains into the PFTBT acceptor block, generating an amphiphilic system. The chemical disparity of the donor and acceptor blocks allowed the development of a purification strategy capable of isolating the desired BCP from homopolymer contaminants. This is a significant improvement over previous systems in which homopolymer contaminants can dominate the reaction mixture, affecting performance and morphology. We show that preliminary morphological analysis indicates spontaneous phase separation in thin films, demonstrating the efficacy of this design strategy and the potential application of these materials in organic photovoltaic devices. Hydrophilic tetraethylene glycol moieties are incorporated into the electron-accepting block of a donor–acceptor block copolymer (BCP) to afford two novel amphiphilic materials based on the P3HT-b-PFTBT scaffold. These amphiphilic BCPs are designed to provide enhanced morphological control as organic photovoltaic active layer materials. The chemical disparity introduced by the hydrophilic side chains enabled the design of a purification system capable of isolating the BCP product, an advantage over previously reported systems.

Selective Detection of Calcium Cations on Macromolecular Langmuir Monolayer and Langmuir-Schaefer Films

In this study, we report the interfacial Langmuir monolayer behavior and surface morphological features of a dendronic terthiophene linked via a tetraethylene glycol moiety (3T5O3T) and its complexation with calcium cations. Surface pressure-mean molecular area (pi-A) isotherms show distinct behavior due to the secondary interaction of cations with the ionophore units. Furthermore, two Langmuir-Schaefer (LS) films with and without calcium cations exhibited significantly different surface morphological features from atomic force microscopy (AFM) imaging. Quartz crystal microbalance (QCM) measurements reveal changes in frequency and resistance enabling selective sensing of calcium cations on the LS films. Thus, well-organized 3T5O3T LS films on the solid substrates are potential candidates for highly selective chemosensing.

Design, Synthesis, and Initial Biological Evaluation of a Steroidal Anti-Estrogen–Doxorubicin Bioconjugate for Targeting Estrogen Receptor-Positive Breast Cancer Cells

As part of our program to develop breast cancer specific therapeutic agents, we have synthesized a conjugate agent that is a conjugate of the steroidal anti-estrogen and the potent cytotoxin doxorubicin. In this effort, we employed a modular assembly approach to prepare a novel 11β-substituted steroidal anti-estrogen functionalized with an azido-tetraethylene glycol moiety, which could be coupled to a complementary doxorubicin benzoyl hydrazone functionalized with a propargyl tetraethylene glycol moiety. Huisgen [3 + 2] cycloaddition chemistry gave the final hybrid that was evaluated for selective uptake and cytotoxicity in ER(+)-MCF-7 and ER(-)-MDA-MB-231 breast cancer cell lines. The results demonstrated that the presence of the anti-estrogenic component in the hybrid compound was critical for selectivity and cytotoxicity in ER(+)-MCF-7 human breast cancer cells as the hybrid was ~70-fold more potent than doxorubicin in inhibition of cell proliferation and promoting cell death.

Highly Sensitive and Selective “Turn-on” Calcium Cation Sensing from a Dendronic Terthiophene Tetraethylene Glycol (TEG) Molecule

A molecule consisting of a branched or dendronic terthiophene with tetraethylene glycol moiety (3T5O) was synthesized for highly sensitive and selective calcium ion detection in solution. The sulfur atoms of the terthiophene dendron moiety contribute to the metal-ligand complexation of calcium cations. The modification of the terthiophene dendrons with a hydroxyl-terminated tetraethylene glycol (TEG) group produces a twisted intramolecular charge transfer (TICT) event in which the terthiophene moiety is conformationally twisted, affecting its chromophoric and fluorophoric activity. This twisted conformation resulted in an increase in emission intensity at 320 nm, at the same time producing a blue shift in the absorption spectra. This process enabled a "turn-on" system for calcium ion detection compared to most "turn-off" systems involving a quenching route. The intensity of the emission is related to saturation of the terthiophene moiety at a concentration of 3T5O:[Ca(2+)] 1:4, of ∼1 × 10(-8) M, which indicates high sensitivity for calcium cations. No response with other cations such as Na(+), K(+), and Mg(2+) was observed, which also indicates high selectivity for the system. Conformational analysis of the 3T5O and the twisted terthiophene dendron geometry was done by semiempirical PM3 modeling. In an effort to distinguish specific interactions between monovalent and divalent cations and the 3T5O, restricted Hartree-Fock level calculations using the STO-3G basis set were also performed. The calculations correlated with the experimental results.

ChemInform Abstract: Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium‐Catalyzed Suzuki—Miyaura Coupling Reaction.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium-Catalyzed Suzuki-Miyaura Coupling Reaction

Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium-Catalyzed Suzuki-Miyaura Coupling Reaction

Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium‐Catalyzed Suzuki–Miyaura Coupling Reaction

Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium‐Catalyzed Suzuki–Miyaura Coupling Reaction

Synthesis of novel glycoconjugates and evaluation as inhibitors against β-glucosidase from almond

Hydrolytic activity of glycosidases can be influenced by inhibitors of glycosidic nature. We have synthetized a serie of glycoconjugates consisting of galactose, glucosaminide or lactose 1- O-linked with allyl alcohol, pentenol or tetraethyleneglycol moieties. These compounds were found to be inhibitors of the hydrolase activity of the β-glucosidase from almond, with K i in the range of 7.7–107 mM and presenting different types of inhibition. Based on the structure of the functionalized glycosides and the inhibition studies performed, we suggest that the nature of the carbohydrate is determinant in the inhibitory strength of these glycoconjugates.

Syntheses of Novel Galoctosyl Ligands for Liposomes and the Influence of the Spacer on Accumulation in the Rat Liver.

We modified the surface of liposomes with galactosyl ligands. At first we determined whether or not the galactosyl moiety was exposed on the liposomes. We then investigated the effect of the ligands on the hepatic accumulation of liposomes in rats. We introduced an oligoethylene glycol moiety as a spacer. Among the various ligands tested, those with a tri- or tetraethylene glycol moiety as a spacer caused the greatest accumulation of liposomes in the liver. Liposomes bearing ligands with a tri- or tetraethylene glycol moiety as a spacer, were aggregated by Ricinus communis agglutinin. On the other hand, those modified with ligands with a mono- or diethylene glycol spacer did not clearly agglutinate. These results show the importance of a spacer between the homing device and the ligand anchor.