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Some frog species have a unique skeletal element, referred to as the intercalary element (IE), in the joints between the terminal and subterminal phalanges of all digits. IEs are composed of cartilage or connective tissue and have a markedly differ shape than the phalanges. IEs are highly related to the arboreal lifestyle and toe pads. The IE is found only in neobatrachian frogs among anurans, suggesting that it is a novelty of Neobatrachia. IEs are widely distributed among multiple neobatrachian lineages and are found in the suborders Hyloides and Ranoides (the two major clades in Neobatrachia). However, it is unclear whether the IEs found in multiple linages resulted from convergent evolution. Therefore, in this study, we aimed to examine how similar or different the developmental trajectories of the IEs are between Hyloides and Ranoides. To that end, we compared the osteological and histological developmental processes of the IEs of the hyloid frog Dryophytes japonicus and the ranoid frog Zhangixalus schlegelii. Both species shared the same IE‐initiation site and level of tissue differentiation around the IE when it began to form in tadpoles, although the IE developments initiated at different stages which were determined by external criteria. These results suggest that similar mechanisms drive IE formation in the digits of both species, supporting the hypothesis that the IEs did not evolve convergently. [ABSTRACT FROM AUTHOR]

The effect of partial replacement of Cu ions by small Be cations with no d-electrons in CaCu3Ti4O12ceramics was studied over the temperature range from 90 K to 800 K. Dielectric constant of CaCu3(1−x)Be3xTi4O12decreases exponentially with increasing x as ε′ =4000 + exp(-x/0.023); by 5% of Be-doping, the relaxation time and activation energy decrease to values of 50% and 92% compared with those in pure CCTO, respectively. The weakened hybridization in Cu-O bonds by Be-doping suppresses dielectric properties. This evidence indicates that the role ofA′-site ions is important for anomalous dielectric response in CaCu3Ti4O12at high temperatures. [ABSTRACT FROM AUTHOR]

Abstract: The regioselective carbonylation of unactivated C(sp3)–H bonds of aliphatic amides, using 2-pyridinylmethylamine as a directing group in conjunction with Ru3(CO)12 as a catalyst is described. The presence of a 2-pyridinylmethylamine moiety in the amides is crucial for the success of the reaction. Although ethylene is not incorporated into the products, its presence is also essential for the reaction to proceed. Furthermore, the addition of H2O is important for the reaction to proceed efficiently. The reaction shows a high preference for the C–H bonds of methyl groups, compared to methylene C–H bonds, even the methylene C–H bonds are activated by the presence of an oxygen atom or an aryl group. In addition, the reaction tolerates various functional groups, such as MeO, Cl, CF3, CN, and even Br substituents. The reaction of α-mono-substituted aliphatic amides gave the corresponding carbonylation products in lower yields, although the use of α,α-di-substituted aliphatic amides resulted in high product yields. The use of a sterically demanding directing group, such as 1-(2-pyridinylethyl)amine moiety, in α-mono-substituted aliphatic amides improved the yields of the products. The stoichiometric reaction of an amide with Ru3(CO)12 gave a stable di-nuclear ruthenium complex as a single ruthenium complex in which the 2-pyridinylmethylamino moiety is coordinated to the ruthenium center in a N,N-manner and an amide carbonyl oxygen binds to the other ruthenium center, but C–H bond activation is not involved. The complex itself does not show catalytic activity, but is activated in the presence of H2O under the catalytic reaction conditions employed. [Copyright &y& Elsevier]

The article offers information regarding the carbonylation of C-H bonds in arylacetamides. It presents the use of bidentate chelation system for the activation of C-H bonds. It mentions the importance of regioselectivity in the transformation of C-H bonds. It states the use of directing group for overcoming the regio-control issues of the catalytic reactions.

The regioselective carbonylation of unactivated C(sp3)-H bonds of aliphatic amides was achieved using Ru3(CO)12 as a catalyst. The presence of a 2-pyridinylmethylamine moiety in the amide is crucial for a successful reaction. The reaction shows a preference for C-H bonds of methyl groups as opposed to methylene C-H bonds and tolerates a variety of functional groups. The stoichiometric reaction of an amide with Ru3(CO)12 gave a dinuclear ruthenium complex in which the 2-pyridinyl-methylamino moiety was coordinated to the ruthenium center in an N,N manner. [ABSTRACT FROM AUTHOR]

A novel method for the cyclocarbonylation of unactivated C-H bonds is developed by using the catalyst Ru3(CO)12. [ABSTRACT FROM AUTHOR]

The presence of a 2-pyridylmethylamine moiety (Pym) as a bidentate directing group is essential for successful carbonylation of the substrates to produce isoquinoline diones and related heterocyclic systems. [ABSTRACT FROM AUTHOR]