Involvement of DPY19L3 in Myogenic Differentiation of C2C12 Myoblasts

DPY19L3 has been identified as a C-mannosyltransferase for thrombospondin type-1 repeat domain-containing proteins. In this study, we focused on the role of DPY19L3 in the myogenic differentiation of C2C12 mouse myoblast cells. We carried out DPY19L3 gene depletion using the CRISPR/Cas9 system. The result showed that these DPY19L3-knockout cells could not be induced for differentiation. Moreover, the phosphorylation levels of MEK/ERK and p70S6K were suppressed in the DPY19L3-knockout cells compared with that of parent cells, suggesting that the protein(s) that is(are) DPY19L3-mediated C-mannosylated and regulate(s) MEK/ERK or p70S6K signaling is(are) required for the differentiation.     

High-performance liquid chromatographic determination and metabolic study of sennoside a in daiokanzoto by mouse intestinal bacteria

Daiokanzoto (DKT, combination of rhubarb and glycyrrhiza), a Kampo medicine, is clinically effective for constipation. Sennoside A is well known to induce diarrhea. Sennoside A is a prodrug that is transformed into an active metabolite, rheinanthrone, by intestinal bacteria. In this study, we investigated the effects of glycyrrhiza on the activity of sennoside A metabolism in intestinal bacteria using mouse feces. A high-performance liquid chromatography (HPLC) method for the determination of sennoside A in incubation mixture of DKT with mouse feces was established. The retention time of sennoside A was 9.26±0.02 min with a TSKgel ODS-80TsQA column by linear gradient elution using a mobile phase containing aqueous phosphoric acid and acetonitrile and detection at 265 nm. We found that the activity of sennoside A metabolism in intestinal bacteria was significantly accelerated when glycyrrhiza, liquiritin or liquiritin apioside coexisted with sennoside A, whereas that of glycyrrhizin was not altered. This method is applicable for determination of the activity of sennoside A metabolism by anaerobic incubation of DKT with mouse feces.     

Asymmetric Organocatalyzed Michael Addition of Nitromethane to a 2‐Oxoindoline‐3‐ylidene Acetaldehyde and the Three One‐Pot Sequential Synthesis of (−)‐Horsfiline and (−)‐Coerulescine

(?)‐Horsfiline and (?)‐coerulescine were synthesized through three one‐pot operations in 33 and 46 % overall yield, respectively. Key to the success was the efficient use of a diarylprolinol silyl ether to catalyze the asymmetric Michael addition of nitromethane to a 2‐oxoindoline‐3‐ylidene acetaldehyde. This allowed the all‐carbon quaternary, spirocyclic carbon stereocenter to be constructed in good yield with excellent enantioselectivity.     

Oxovanadium(V)-Catalyzed Deoxygenative Coupling Reaction of Alcohols with Trimethylsilyl Enol Ethers in the Presence of MS3A

Oxovanadium(V)-catalyzed deoxygenative coupling reaction of allyl alcohols with trimethylsilyl enol ethers was demonstrated to afford γ,δ-unsaturated carbonyl compounds in one-step. The catalytic deoxygenative coupling reaction of allyl alcohols proceeded smoothly with both aromatic and aliphatic trimethylsilyl enol ethers. This catalytic deoxygenative coupling system could be applied to the deoxygenative coupling reaction of benzyl alcohols with trimethylsilyl enol ethers, providing the corresponding carbonyl compounds. Furthermore, a gram-scale catalytic synthesis of the γ,δ-unsaturated carbonyl compound was successfully performed to validate the scalability of this catalytic deoxygenative coupling reaction.     

Self‐Assembled Boronic Ester Cavitand Capsules with Various Bis(catechol) Linkers: Cavity‐Expanded and Chiral Capsules

Two molecules of cavitand tetraboronic acid and four molecules of various bis(catechol) linkers self‐assemble into capsules through the formation of eight dynamic boronic ester bonds. Each capsule has a different cavity size depending on the linker used, and shows particular guest encapsulation selectivity. A chiral capsule made up of the cavitand and a chiral bis(catechol) linker was also constructed. This capsule induces supramolecular chirality with respect to a prochiral biphenyl guest by diastereomeric encapsulation through the asymmetric suppression of rotation around the axis of the prochiral biphenyl moiety.     

The reaction of acetal-type protective groups in combination with TMSOTf and 2,2′-bipyridyl; mild and chemoselective deprotection and direct conversion to other protective groups

A mild and chemoselective deprotection method of various acetal-type protective groups, such as MOM, MEM, BOM, and SEM ethers, has been developed. The combination of TMSOTf and 2,2′-bipyridyl was very effective for the deprotection, and the reaction proceeded via the formation of pyridinium intermediates, which were hydrolyzed to the corresponding alcohols in good to high yields. The features of this method are mild (almost neutral) reaction conditions and the tolerability of acid-sensitive functional groups. This method is also applicable for the direct conversion of MOM ether to BOM or SEM ether using the appropriate alcohols instead of H₂O.     

Synthesis of a head-to-tail-type cyclodextrin-based insulated molecular wire

We developed a new method for synthesizing an organic-soluble insulated molecular wire (IMW) using permethylated cyclodextrin (PMCD). The IMW obtained using this method is highly soluble in a variety of organic solvents and has a high covering ratio, regioregularity, rigidity, photoluminescence efficiency, and interchain hole mobility.     

Synthesis and efficient circularly polarized light emission of an optically active hyperbranched poly(fluorenevinylene) derivative

An optically active, hyperbranched poly(fluorenevinylene) derivative was synthesized by polymerization of (-)-2,4,7-tris(bromomethyl)-9-neomenthyl-9-pentylfluorene. A spin-coated film sample of the polymer exhibited efficient circularly polarized light (CPL) emission in the visible range of 400-700 nm on photo excitation even without annealing processes leading to chain ordering.