Copper-Catalyzed Aza-Michael Addition of 2‑Aminobenzoate to β‑Substituted α,β-Unsaturated Ketones: One-Pot Synthesis of 3‑Carbonyl-2-Substituted Quinolin-4(1<i>H</i>)‑ones

We present a new and straightforward one-pot process for the synthesis of 3-carbonyl-4-quinolone derivatives through highly efficient Cu-catalyzed aza-Michael addition of 2-aminobenzoates to β-substituted α,β-unsaturated ketones/cyclization/mild oxidation reactions. A broad range of new versatile 3-carbonyl-quinolin-4­(1<i>H</i>)-ones is prepared from readily available chemicals under mild reaction conditions with short reaction times, producing good to excellent yields (up to 99%)

Manganese Complex of Ethylene­diamine­tetraacetic Acid (EDTA)–Benzothiazole Aniline (BTA) Conjugate as a Potential Liver-Targeting MRI Contrast Agent

A novel manganese­(II) complex based on an ethylene­diamine­tetraacetic acid (EDTA) coordination cage bearing a benzothiazole aniline (BTA) moiety (Mn-EDTA-BTA) was designed and synthesized for use as a liver-specific MRI contrast agent with high chelation stability. In addition to forming a hydrophilic, stable complex with Mn²⁺, this new Mn chelate was rapidly taken up by liver hepatocytes and excreted by the kidneys and biliary system. The kinetic inertness and <i>R</i>₁ relaxivity of the complex were much higher than those of mangafodipir trisodium (MnDPDP), a clinically approved liver-specific MRI contrast agent. The diagnostic utility of this new Mn complex in MRI was demonstrated by high-sensitivity tumor detection in an animal model of liver cancer

Gadolinium Complex of 1,4,7,10-Tetraazacyclo­dodecane-1,4,7-trisacetic Acid (DO3A)–Ethoxybenzyl (EOB) Conjugate as a New Macrocyclic Hepatobiliary MRI Contrast Agent

We report the synthesis of a macrocyclic Gd chelate based on a 1,4,7,10-tetraazacyclo­dodecane-1,4,7-trisacetic acid (DO3A) coordinationn cage bearing an ethoxybenzyl (EOB) moiety and discuss its use as a <i>T</i>₁ hepatobiliary magnetic resonance imaging (MRI) contrast agent. The new macrocyclic liver agent shows high chelation stability and high <i>r</i>₁ relaxivity compared with linear-type Gd chelates, which are the current clinically approved liver agents. Our macrocyclic, liver-specific Gd chelate was evaluated in vivo through biodistribution analysis and liver MRI, which demonstrated its high tumor detection sensitivity and suggested that the new Gd complex is a promising contrast agent for liver cancer imaging

Understanding the Bifunctional Effect for Removal of CO Poisoning: Blend of a Platinum Nanocatalyst and Hydrous Ruthenium Oxide as a Model System

CO poisoning of Pt catalysts is one of the most critical problems that deteriorate the electrocatalytic oxidation and reduction reactions taking place in fuel cells. In general, enhancing CO oxidation properties of catalysts by tailoring the electronic structure of Pt (electronic effect) or increasing the amount of supplied oxygen species (bifunctional effect), which is the typical reactant for CO oxidation, has been performed to remove CO from the Pt surface. However, though there have been a few reports about the understanding of the electronic effect for rapid CO oxidation, a separate understanding of bifunctional modification is yet to be achieved. Herein, we report experimental investigations of CO oxidation in the absence of electronic effect and an extended concept of the bifunctional effect. A model system was prepared by blending conventional Pt/C catalysts with hydrous ruthenium oxide particles, and the CO oxidation behaviors were investigated by various electrochemical measurements, including CO stripping and bulk oxidation. In addition, this system allowed the observation of CO removal by the Eley–Rideal mechanism at high CO coverages, which facilitates further CO oxidation by triggering the CO removal by the Langmuir–Hinshelwood mechanism. Furthermore, effective CO management by this approach in practical applications was also verified by single-cell analysis