Yaequinolones J1 and J2, novel insecticidal antibiotics from Penicillium sp. FKI-2140

[chemical reaction: see text]. Two novel insecticidal antibiotics with a p-methoxyphenylquinolinone skeleton fused with a pyran ring, yaequinolones J1 (1) and J2 (2), have been isolated from Penicillium sp. FKI-2140, and structures were elucidated by spectroscopic studies including various NMR experiments. The relative stereochemistries were assigned by NOE experiments. Yaequinolones J1 and J2 showed toxicity against Artemia salina (brine shrimp) with the MIC value of 6.25 microg/mL.     

Least energy solutions of the generalized Hénon equation in reflectionally symmetric or point symmetric domains

We study the generalized Hénon equation in reflectionally symmetric or point symmetric domains and prove that a least energy solution is neither reflectionally symmetric nor even. Moreover, we prove the existence of a positive solution with prescribed exact symmetry.     

Size-dependent reactivity of cobalt cluster ions with nitrogen monoxide: Competition between chemisorption and decomposition of NO

Reactions of NO molecules on cobalt cluster ions were studied in a beam-gas geometry by using a tandem mass spectrometer. Single-particle collision reactions of Co_mNO⁺ (m = 3–10) with NO were found to proceed in such a manner that NO decomposition dominates at m = 4–6 with the maximum reaction cross section at m = 5 and chemisorption dominates in m ≥ 7. On the other hand, in two-particle collision reactions of Co_n⁺ (n = 2–10) with NO, NO decomposition at n ≥ 5 and chemisorption of two NO molecules with Co atoms loss at n ≥ 8 were found to proceed. These results indicate that the size-dependency of the multiple collision reactions originates from secondary attacking of an NO molecule to primary products of the initial single collision reactions. The DFT calculation supports the scheme that both the decomposition and chemisorption of two-particle collision reactions proceed via a common intermediate, Co_mN₂O₂⁺, in which the two NO molecules are dissociatively chemisorbed on the cobalt cluster ion, and the size-dependency of the two-particle collision reactions is explained in terms of the structure of this reaction intermediate.     

Lariatins, antimycobacterial peptides produced by Rhodococcus sp. K01-B0171, have a lasso structure

Two antimycobacterial agents, lariatins A and B, were isolated from the culture broth of Rhodococcus sp. K01-B0171. Their structures were elucidated by spectral analysis and advanced protein chemical methods to be unique cyclic peptides, which consist of 18 and 20 L-amino acid residues with an internal linkage between the gamma-carboxyl group of Glu8 and the alpha-amino group of Gly1. The three-dimensional structure of lariatin A deduced from NMR data by dynamical simulated annealing method indicates that the tail segment (Trp9-Pro18) passes through the ring segment (Gly1-Glu8) to form a 'lasso' structure.     

Microfluidic control of the internal morphology in nanofiber-based macroscopic cables

A matter of orientation: The nanofibers in cables that consist of assemblies of these nanofibers can be oriented parallel or perpendicular to the longitudinal axis by regulating the fluidic velocities of the core and sheath flows in coaxial microfluidic devices. Control of the internal morphology enables fabrication of cables with improved electrical conductivity and mechanical properties.     

Single-vesicle estimation of ATP-binding cassette transporters in microfluidic channels

We have developed a method to analyze the substrate transport of ATP-binding cassette (ABC) transporters, which are associated with drug resistance in tumor cells. Our microfluidic method is well suited to the single-vesicle estimation of substrate transport and the rapid drug screening of ABC transporters. Using this method, we have demonstrated, for the first time, the analysis of substrate transport by a single transporter and performed drug-inhibition experiments in less than 3 h.     

Convenient Method of Chain‐Growth Polycondensation for Well‐Defined Aromatic Polyamides

Summary: For the convenient synthesis of well‐defined poly(N‐octyl‐p‐benzamide)s with low polydispersities, the polycondensation of methyl 4‐octylaminobenzoate ( 1 ) was investigated. Methyl ester monomer 1 polymerized with lithium 1,1,1,3,3,3‐hexamethyldisilazide (LHMDS) in the presence of an initiator in tetrahydrofuran at −10 °C. The highly pure polyamide with a defined molecular weight and a low polydispersity is obtained after simple treatment of the reaction mixture with aqueous NaOH solution, followed by evaporation.

The chain‐growth polycondensation of 4‐octylaminobenzoic acid methyl ester ( 1 ) with lithium 1,1,1,3,3,3‐hexamethyldisilazide (LHMDS) to yield poly(N‐octyl‐p‐benzamide).     

Rational Molecular Design towards Vis/NIR Absorption and Fluorescence by using Pyrrolopyrrole aza‐BODIPY and its Highly Conjugated Structures for Organic Photovoltaics

Pyrrolopyrrole aza‐BODIPY (PPAB) developed in our recent study from diketopyrrolopyrrole by titanium tetrachloride‐mediated Schiff‐base formation reaction with heteroaromatic amines is a highly potential chromophore due to its intense absorption and fluorescence in the visible region and high fluorescence quantum yield, which is greater than 0.8. To control the absorption and fluorescence of PPAB, particularly in the near‐infrared (NIR) region, further molecular design was performed using DFT calculations. This results in the postulation that the HOMO–LUMO gap of PPAB is perturbed by the heteroaromatic moieties and the aryl‐substituents. Based on this molecular design, a series of new PPAB molecules was synthesized, in which the largest redshifts of the absorption and fluorescence maxima up to 803 and 850 nm, respectively, were achieved for a PPAB consisting of benzothiazole rings and terthienyl substituents. In contrast to the sharp absorption of PPAB, a PPAB dimer, which was prepared by a cross‐coupling reaction of PPAB monomers, exhibited panchromatic absorption across the UV/Vis/NIR regions. With this series of PPAB chromophores in hand, a potential application of PPAB as an optoelectronic material was investigated. After identifying a suitable PPAB molecule for application in organic photovoltaic cells based on evaluation using time‐resolved microwave conductivity measurements, a maximized power conversion efficiency of 1.27 % was achieved.     

Synthesis of 2-phenylimidazo[2,1-b]benzothiazole derivatives as modulators of multidrug resistance for tumor cells

We have investigated 3-substituted-2-phenylimidazo[2,1-b]benzothiazole derivatives and herein we have discussed their pharmaceutical activities. We found that some 2-phenyl-5,6,7,8-tetrahydroimidazo[2,1-b]-benzothiazoles could overcome multidrug resistance for tumor cells. Among them, 2-phenyl-3-(N-methyl-3-piperidyl)carbonylammomiinomemyl-5,6,7,8-tetrahydVoimidazo[2,1-b]benzothiazole [N276-12] demonstrated the most potent activity for overcoming multidrug resistance.     

Synthesis of 2-aminoazulene derivatives. Nucleophilic and palladium-catalyzed amination of 2-substituted azulene

Amination of 2-substituted azulene was carefully examined using several types of amines, and the scope and limitation of substrates and reagents in these direct nucleophilic aminations were found. The synthesis of 2-aminoazulenes was successfully achieved by the reaction of 2-bromoazulene with several amines via palladium-catalyzed amination.