Search results for "Pyridine"

Retrospective Study of Regorafenib Versus TAS-102 Efficacy and Safety in Chemorefractory Metastatic Colorectal Cancer (mCRC) Patients: A Multi-instit…

2021

INTRODUCTION: There have been significant developments in colorectal cancer (CRC) research over the last few years, with the introduction of new agents that have been prolonged median overall survival of metastatic colorectal cancer (mCRC). These therapies have improved patient outcomes; however, despite significant progress in strategies for cancer treatment, their use is limited by development of resistant mechanism. Almost 30% of patients with refractory mCRC will remain good candidates for further treatment. Regorafenib and TAS-102 are novel antitumor agents for patients with refractory mCRC. However, it is unclear which patients may derive a survival benefit from these drugs in real-li…

Synthesis of rigid ethynyl-bridged polytopic picolinate ligands for MOF applications

2015

Abstract Segmented homopolytopic ligands that consist of a rigid central arylene platform, ethynylene spacers, and terminal chelating picolinate subunits have been synthesized in good yields in a two-step procedure involving a Sonogashira-type cross coupling reaction between the ester methyl 5-bromopyridine-2-carboxylate and several arylacetylenes, followed by hydrolysis of the resulting methyl picolinates. A similar strategy has been employed for the preparation of heteroditopic ligands containing picolinate and a second non-chelating pyridine or benzoate unit. The compounds are potential candidates for organic linkers in metal–organic frameworks (MOFs).

Synthesis and radical coupling of pyridine-bridged π-extended tetrathiafulvalene (TTF)-type donors and push–pull analogues

2007

A new family of pi-extended TTF analogues (3a-c) and D-pi-A chromophores (5a-c), in which the electroactive units (1,3-dithiole rings and 2,2-dicyanovinyl groups) are connected through a pyridine bridge with a meta substitution pattern, is reported. The redox behavior of these compounds has been investigated by cyclic voltammetry and theoretical calculations performed at the B3P86/6-31G** level. Unlike many pi-extended TTF derivatives, the 1,3-dithiole rings in compounds 3a-c do not behave independently and two oxidation processes are observed with an anodic separation ranging from 50 to 150 mV. Calculations show that electrons are equally extracted from both dithiole rings. A biradical str…

Organometallic nucleophiles.A mechanistic study of halide displacement at saturated carbon by 2- and 4-pyridyl complexes of palladium (II) and platin…

1996

Abstract The reactions of the 2- and 4-pyridyl complexes [MX(C 5 H 4 N C n )(dppe)] and trans -[MX(C 5 H 4 N C n )(PPh 3 ) 2 ] (M  Pd, Pt; X  Cl, Br; n = 2, 4)- involving halide displacement from the organic halides XCH 2 R (X  Cl, Br; R  CN, Ph, CH  CH 2 ) by the pyridyl nitrogen have been studied kinetically by conductivity in acetone or acetonitrile at 25°C. The kinetic data fit the second-order rate law rate k 2 [XCH 2 R][complex], in agreement with an S N 2 process at saturated carbon. The higher rates are displayed by the 2-pyridylplatinum derivatives with X  Br in both the metal complex and the organic halide. The higher nucleophilic power of the 2-pyridyl complexes compare…

Triazolopyridines 20. Hydrogenation reactions

1999

Abstract Hydrogenation reactions of some [1,2,3]triazolo[1,5-a]pyridines and their benzo derivatives, [1,2,3]-triazolo[1,5-a]quinoline and [1,2,3]triazolo[5,1-a]isoquinoline are studied. In general, the pyridine ring is more easily hydrogenated than the triazole or benzene rings.

Inside Cover: A Boron Dipyrromethene (BODIPY)-Based CuII-Bipyridine Complex for Highly Selective NO Detection (Chem. Eur. J. 44/2015)

2015

Synthesis, physicochemical and electrochemical properties of metal–metal bonded ruthenium corrole homodimers

2002

Abstract Two diruthenium(III,III) corrole dimers, [(Et 6 Me 2 Cor)Ru] 2 and [(Me 6 Et 2 Cor)Ru] 2 , where Et 6 Me 2 Cor and Me 6 Et 2 Cor are the 2,3,8,12,17,18-hexaethyl-7,13-dimethylcorrole and 8,12-diethyl-2,3,7,13,17,18-hexamethylcorrole trianions, respectively, were synthesized and characterized as to their spectroscopic and electrochemical properties. They exhibit up to three oxidations and two reductions by cyclic voltammetry in CH 2 Cl 2 or pyridine containing 0.1 M TBAP, almost all of which are electrochemically reversible on the voltammetric and/or thin-layer spectroelectrochemical timescale. The two reductions and the first two oxidations involve one-electron transfer processes w…

PREPARATION AND REACTIONS OF 2-PYRIDYLPLATINUM(II) COMPLEXES [PTCL(C5H4N-C2)(TERTIARY PHOSPHINE)2] - COMPOUNDS WITH A MARKEDLY NUCLEOPHILIC PYRIDINE …

1989

Abstract The 2-pyridyl complex trans -[PtCl(C 5 H 4 N- C 2 )(PPh 3 ) 2 ] (I) can be prepared in high yield by oxidative addition of 2-chloropyridine to [Pt(PPh 3 ) 4 ]. The reaction of I with 1,2-bis(diphenylphosphino)ethane yields the cis derivative [PtCl(C 4 5 H 4 N- C 2 )(dppe)] (II). In polar solvents, the latter rearranges to the binuclear cationic complex [Pt(μ-C 5 H 4 N- C 2 , N )(dppe)] 2 Cl 2 . The reaction of I with [PdCl(η 3 -2-MeC 3 H 4 )] 2 (1/0.5 molar ratio) gives the products [PtCl(μ-C 5 H 4 N- C 2 , N )(PPh 3 )] 2 (IV) and [PdCl(η 3 -2-MeC 3 H 4 )(PPh 3 )]. 31 P NMR monitoring of the reaction suggests that PPh 3 transfer occurs in a binuclear platinum/palladium intermediate…

New heteronuclear gold(I)-platinum(II) complexes with cytotoxic properties: are two metals better than one?

2014

A series of mono- and heterodinuclear gold(I) and platinum(II) complexes with a new bipyridylamine-phosphine ligand have been synthesized and characterized. The X-ray structures of the ligand precursor 4-iodo-N,N-di(pyridin-2-yl)benzamide, and of one gold derivative are reported. All the complexes display antiproliferative properties in vitro in human cancer cells in the range of cisplatin or higher, which appear to correlate with compounds' uptake. Interestingly, studies of the interactions of the compounds with models of DNA indicate different mechanisms of actions with respect to cisplatin. The biological activity study of these complexes provides useful information about the interest of…

Influence of the functionalisation of mesoporous silica material UVM-7 on polyphenol oxidase enzyme capture and enzymatic browning

2020

Polyphenol oxidase (PPO), also known as tyrosinase and catechol oxidase, is the enzyme responsible for enzymatic browning in foods. It causes undesirable organoleptic, nutritional and colour changes. Here, we report the preparation of five nanomaterials and a study of their ability to modulate PPO enzyme activity. The materials consist of UVM-7 supports (a mesoporous silica material) modified with diverse functional groups (i.e. amine, carboxylic acid, isocyanate, alkane and pyridine). We also studied the PPO immobilisation capability of the materials. All the materials, except the carboxylic acid functionalised one, offer high PPO loading capabilities and the immobilisation speed increases…