Rhodium-catalyzed reaction of terminal alkynes with allylamine leading to (E)-3-alkylidene N-heterocycles

Terminal alkynes react with allylamine in the presence of a RhCl(PPh3)3 catalyst to give (E)-3-alkylidene-3,4-dihydro-2H-pyrroles. The products consist of two molecules of alkyne and one molecule of allylamine. Although dimers, trimers, and oligomers of alkynes are also obtained as byproducts, the addition of various ammonium salts to the reaction suppresses such oligomerization, resulting in an increase in product.     

Rhodium-catalyzed synthesis of germoles via the activation of carbon-germanium bonds

The rhodium-catalyzed reaction of 2-germylphenylboronic esters with alkynes in the presence of a rhodium(I) catalyst is established as a modular method for the synthesis of an array of benzogermole derivatives. The reaction proceeds through the activation of C(sp(3))-Ge bonds. The mechanism of this new bond activation process is discussed based on the activation aptitude of alkyl and aryl substituents on germanium.     

Nickel-catalyzed chelation-assisted transformations involving ortho C-H bond activation: regioselective oxidative cycloaddition of aromatic amides to alkynes

Although the pioneering example of ortho metalation involving cleavage of C-H bonds was achieved using a nickel complex (Kleiman, J. P.; Dubeck, M. J. Am. Chem. Soc. 1963, 85, 1544), no examples of catalysis using nickel complexes have been reported. In this work, the Ni-catalyzed transformation of ortho C-H bonds utilizing chelation assistance, such as oxidative cycloaddition of aromatic amides with alkynes, has been achieved.     

Palladium-catalyzed direct ethynylation of C(sp3)-H bonds in aliphatic carboxylic acid derivatives

The first catalytic alkynylation of unactivated C(sp(3))-H bonds has been accomplished. The method allows for the straightforward introduction of an ethynyl group into aliphatic acid derivatives under palladium catalysis. This new reaction can be applied to the rapid elaboration of complex aliphatic acids, for example, via azide/alkyne cycloaddition.     

Visualization of liver uptake function using the uptake contrast-enhanced ratio in hepatobiliary phase imaging

Purpose

To visualize liver uptake function using the uptake contrast-enhanced ratio in hepatobiliary phase (uptake CERH) magnetic resonance imaging.

Materials and methods

Thirty-seven patients with hepatocellular carcinoma (HCC) and 23 with metastatic liver cancer were evaluated. Hepatobiliary phase images were acquired 20 min after an intravenous bolus injection of gadoxetic acid disodium. We assumed that the contrast-enhanced ratio in the hepatobiliary phase (CERH) in the spleen was similar to the contrast-enhanced ratio in the extracellular matrix (CEREM). The Uptake CERH value was defined as the percentage signal gain between the precontrast and hepatobiliary phase images (without CEREM). The Uptake CERH value measured the tumor-free liver parenchyma. The association of the uptake CERH value with the biochemical liver function test results, and hepatocellular density in the liver parenchyma was assessed. Correlations were examined using Pearson correlation coefficient and the Mann–Whitney test.

Results

The uptake CERH value was correlated with albumin, bilirubin, indocyanine green retention rate at 15 min, prothrombin activity(%), platelet count, and cellular density in the liver parenchyma (p < 0.01).

Conclusions

Uptake CERH images are useful for visualizing liver uptake function.     

Efficient synthesis of 1-adamantanecarboxaldehyde by the GaCl3-mediated carbonylation of adamantane under mild reaction conditions

The reaction of adamantane (1) with CO (1 atm) in 1,2-dichloroethane at room temperature in the presence of GaCl(3) results in formylation to give 1-adamantanecarboxaldehyde (2) in up to 84% yield.     

Structural studies of polyesters. VIII. Molecular and crystal structure of polydiketene

The molecular and crystal structures of polydiketene were studied by infrared spectroscopy and x-ray diffraction. It was confirmed from the infrared spectra that diketene molecules in the crystal polymerize by ring opening upon γ-ray irradiation. The unit cell of the product as polymerized is orthorhombic, P22₁2₁-D₂³, with a = 5.43 Å, b = 8.94 Å, and c (fiber axis) = 7.75 Å. Two molecules pass through the unit cell The molecule has a conformation shown by the Fischer projection for a lefthanded (2/1) helix; The internal rotation angle around the O—C bond is nearly gauche (?84°), unlike other polyesters. On the basis of x-ray analysis, several molecular conformation models were selected by utilizing calculations of intramolecular interaction energies.     

Ruthenium-catalyzed C-H/CO/Olefin coupling reaction of N-arylpyrazoles. Extraordinary reactivity of N-arylpyrazoles toward carbonylation at C-H bonds

The reaction of 1-arylpyrazoles with CO and ethylene in the presence of Ru(3)(CO)(12) resulted in regioselective carbonylation at the ortho C-H bonds. While it is found that the pyrazole ring also functions as the directing group for C-H bond cleavage, the efficiency of the reaction depends on the position of the pyrazole ring.