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A hydrocarboxylation reaction of alkyne or styrene derivatives with CO2 proceeded smoothly by using an air-stable nano-sized nickel catalyst supported on sulfur-modified gold (SANi), giving functio...

α-Emission radiotherapeutics has potential to be one of most effective cancer therapeutics. Herein, we report a facile synthesis of an 211At-labeled immunoconjugate for use as an α-emission molecular targeting therapy. We synthesized a tetrazine probe modified with closo-decaborate(2-), a prosthetic group that forms a bioavailable stable complex with 211At. Our one-pot three-component double-click labeling method was used to attach decaborate to trastuzumab (anti-HER2 antibody) using decaborate-tetrazine and TCO-aldehyde probes without reducing the antibody binding affinity. Labeling the decaborate-attached trastuzumab with 211At produced in the cyclotron at the RIKEN Nishina Center, at which highly radioactive 211At can be produced, readily furnished the 211At-labeled trastuzumab with a maximum specific activity of 15 MBq μg−1 and retention of the native binding affinity. Intratumor injection of the 211At-labeled trastuzumab in BALB/c nude mice implanted with HER2-expressing epidermoid cancer cells yielded efficient accumulation at the targeted tumor site as well as effective suppression of tumor growth.

A previously unreported 1,5-diazacyclooctane-palladium(II) complex was synthesized using bis[N,N′-(2-indanolyl)]-1,5-diazacyclooctane, which was readily prepared via a novel [4+4] homocyclization of the unsaturated imine intermediate generated from acrolein and 1-amino-2-indanol. Interestingly, the 1,5-diazacyclooctane-palladium(II) complex self-assembled to form palladium nanoparticles. This approach readily provided palladium nanoparticles simply by heating a mixture of palladium(II) acetate and bis[N,N′-(2-indanolyl)]-1,4-diazacyclooctane in dichloroethane at mild temperatures. The 1,5-diazacyclooctane-derivative-palladium nanoparticles were successfully deployed in synthetic applications as a heterogeneous catalyst, facilitating Suzuki coupling and a challenging C–C bond formation via C(sp3)–H activation under low catalyst loading conditions.

One pot double click strategy containing strain-promoted click-reaction followed by 6π-azaelectrocyclization (RIKEN click reaction) has worked well in the synthesis of multivalent homogeneous and heterogeneous N-glycoalbumins. We have slightly changed the structure of linker unsaturated aldehyde used in this method. As a result it can be easily synthesized from commercially available material and furthermore, the enhancement of its reactivity towards both click-reactions was observed. The data described in this Communications facilitate the usage of the double click strategy as a general method for the synthesis of a variety of neo-N-glycoproteins.

We have developed a conceptually and methodologically novel self-assembled multilayer nickel nanoparticle (NP) catalyst – sulfur-modified gold-supported Ni NPs (SANi) – for organic synthesis. The SANi catalyst was easily prepared through a three-step procedure involving simultaneous in situ metal NP and nanospace organization. This unique method does not require any conventional preformed template for immobilizing and stabilizing NPs. SANi catalyzes carbon-carbon bond-forming cross-coupling, Kumada coupling, and Negishi coupling reactions under ligand-free conditions and can be used repeatedly for these reactions. Physical analysis of SANi showed that the active species in these reactions are self-assembled multilayer zerovalent Ni NPs with a size of ∼3 nm.

A one-pot three-component double-click process for preparing tumor-targeting agents for cancer radiotherapy is described here. By utilizing DOTA (or NOTA) containing tetrazines and the TCO-substituted aldehyde, the two click reactions, the tetrazine ligation (an inverse electron-demand Diels-Alder cycloaddition) and the RIKEN click (a rapid 6π-azaelectrocyclization), could simultaneously proceed under mild conditions to afford covalent attachment of the metal chelator DOTA or NOTA to biomolecules such as to albumin and anti-IGSF4 antibody without altering their activities. Subsequently, radiolabeling of DOTA- or NOTA-attached albumin and anti-IGSF4 antibody (an anti-tumor-targeting antibody) with [67Cu], a β−-emitting radionuclide, could be achieved in a highly efficient manner via a simple chelation with DOTA proving to be a more superior chelator than NOTA. Our work provides a new and operationally simple method for introducing the [67Cu] isotope even in large quantities to biomolecules, thereby representing an important process for preparations of clinically relevant tumor-targeting agents for radiotherapy.

In article number 1600394, Almira Kurbangalieva, Katsunori Tanaka, and co‐workers at the RIKEN Biofunctional Synthetic Chemistry Laboratory develop a way to engineer glycan complexes—heterogeneous clusters of sugar chains attached to proteins or lipids—in a way that allows the molecules to be transported preferentially to specific organs of the body through pattern recognition mechanisms, depending on the sugar chains contained in the cluster.

The N-Troc (2,2,2-trichloroethoxycarbonyl) groups in glucosamine and muramic acid derivatives were removed by treatment with tetrabutylammonium fluoride (TBAF) under mild conditions. The use of Troc protection for the amino group in aminosugars such as glucosamine is increasing the importance for selective and efficient glycosylation, and the cleavage method described here will expand the available opportunities for using the Troc group in the preparation of a variety of glycans. This cleavage is especially advantageous for compounds that are labile or may be decomposed under acidic conditions, strong basic conditions, or reductive conditions.

A new method for the removal of the Troc group under mild conditions in a homogeneous reaction is developed.