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Most conformational molecular switches based on an amide skeleton are limited in their use in solution. We developed a molecular switch with an amide skeleton, which is applicable without a solvent. Treatment of solid 3 with HCl vapor (without dissolution) and sublimation switched the amide conformation by converting a dimethylamino group to a dimethylammonium group. The transformation was reversed by sublimation with pumping to remove HCl. This switching, which proceeds in the gas state in sublimation and not the solution state, was confirmed to be an on/off process by crystal analysis. [ABSTRACT FROM AUTHOR]

Dysregulated yes-associated protein (YAP) is involved in several malignant cancers. However, discovering a druggable YAP inhibitor(s) is difficult because YAP itself does not have any enzymatic activity. In such cases, targeted protein degradation strategies based on hybrid molecules that bind to the target protein and an E3 ubiquitin ligase are useful for suppressing proteins that exhibit aberrant activation and/or excessive expression. Upon screening YAP-interacting small compounds, we identified HK13, a platanic acid, as a novel compound that interacts with YAP. Next, we synthesized hybrid compounds of platanic acid and LCL-161, which reportedly shows a high affinity for cIAP, one of E3 ubiquitin ligases. Among these compounds, HK24 possessed the ability to inhibit the growth of YAP overexpressing NCI-H290 cells. This inhibitory activity may be mediated by YAP degradation, although HK24 exhibited weak YAP degradation. Furthermore, we confirmed involvement of proteasome pathway in HK24-dependent YAP degradation by culturing NCI-H290 cells in the presence of a proteasome inhibitor. Therefore, it is possible that platanic acid is a potential candidate for molecular medicine targeting YAP. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic studies of two components of tubulysins, tubulin polymerization inhibitors are described. The highly stereoselective synthesis of tubuvaline methyl ester (2) was accomplished by 1,3-dipolar cycloaddition of nitrone d-6 and acrylic acid derivatives 7 as a key step. The synthesis of tubuphenylalanine (3) was conducted by an aldol reaction of a boron enolate of (S)-4-isopropyl-3-propionyl-2-oxazolidinone (13) with aldehyde 14, readily prepared from phenylalanine, followed by Barton deoxygenation under radical conditions. [Copyright &y& Elsevier]

Oxidative dimerization of 1-naphthols 1 with dioxygen in the presence of a semiconductor, such as SnO2, ZrO2, or activated charcoal, as a catalytic mediator takes place selectively to give the corresponding 2,2′-binaphthols 2 or 2,2′-binaphthyl-1,1′-quinones 3 in excellent yields without light irradiation. The catalytic activity of SnO2 could be fully restored by appropriate reactivation treatment after the oxidation. In addition, SnO2 without dioxygen catalyzes selective O-demethylation of the enol-ethers 3 to 4. [Copyright &y& Elsevier]

Presents a study that examined schemes for improvement of signal to noise ratio (SNR) for thermally stable high performance longitudinal media. Importance of small magnetic grain sizes and distribution in achieving higher SNR; Methodology; Results and discussion.

Activated amide bonds have been attracting intense attention; however, most of the studied moieties have twisted amide character. To add a new strategy to activate amide bonds while maintaining its planarity, we envisioned the introduction of an alkynyl group on the amide nitrogen to disrupt amide resonance by nN→Csp conjugation. In this context, the conformations and properties of N‐ethynyl‐substituted aromatic amides were investigated by DFT calculations, crystallography, and NMR spectroscopic analysis. In contrast to the cis conformational preference of N‐ethyl‐ and vinyl‐substituted acetanilides, N‐ethynyl‐substituted acetanilide favors the trans conformation in the crystal and in solution. It also has a decreased double bond character of the C(O)−N bond, without twisting of the amide. N‐Ethynyl‐substituted acetanilides undergo selective C(O)−N bond or N−C(sp) bond cleavage reactions and have potential applications as activated amides for coupling reactions or easily cleavable tethers. [ABSTRACT FROM AUTHOR]

• Solution and crystal structures of N -aryl- N -(6-azulenyl)acetamides were determined. • The relative π-electron densities of the N -aromatic groups affect the conformation. • The N -(6-azulenyl) group has a very different effect from the N -(2-azulenyl) group. We synthesized a series of N -(6-azulenyl)- N -arylacetamides, and investigated their conformational preferences in solution and in the crystalline state by means of NMR and X-ray analyses. The results indicated that the conformational preferences of these amides are dependent on both the relative π-electron densities of the N -aromatic parts and the three-dimensional relationship of the carbonyl group to the aryl groups. The N -(6-azulenyl) group has a very different effect from the previously reported N -(2-azulenyl) group on the conformational preferences of aromatic amides. [ABSTRACT FROM AUTHOR]

Presents information on a study that investigated the magneto-optical Faraday effect of porous films comprised of cobalt-substituted barium ferrite particles fixed by a resin. Film preparation and measurements; Results and discussion; Conclusion.

In this paper, magnetic and structural properties of near-equiatomic CoPt thin films, which exhibited a high coercivity in the film-normal direction-suitable for perpendicular magnetic recording media applications-are reported. The films exhibited a larger coercivity of about 6.5 kOe at 8 nm. The coercivity showed a monotonous decrease as the film thickness was increased. The transmission electron microscopy images indicated that the as fabricated CoPt film generally consists of a stack of magnetically hard hexagonal-close-packed phase, followed by stacking faults and face-centred-cubic phase. The thickness dependent magnetic properties are explained on the basis of exchange-coupled composite media. Epitaxial growth on Ru layers is a possible factor leading to the unusual observation of magnetically hard hcp-phase at high concentrations of Pt. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Solution and crystal structures of N -aryl- N -(2-azulenyl)acetamides were determined. • The molecular conformation is influenced by the N -aryl group's π-electron density. • The N -(2-azulenyl) group lies almost coplanar with the amide plane. Abstract Aromatic amides bearing 2-azulenyl group on the amide nitrogen were synthesized and their structures were investigated. The π-electron density of the N -aryl group was found to influence the cis - trans conformational preferences of these compounds in solution. X-ray crystallography revealed that the plane of the 2-azulenyl ring has a strong tendency to lie coplanar with the amide plane when the azulene group is located on the same side as the amide oxygen atom. [ABSTRACT FROM AUTHOR]

The cis - trans conformational equilibrium of amides is of interest because it can be used to control functional activity. Here, we designed and synthesized a series of N -(3-thienyl)amides in order to study the factors affecting their conformational equilibrium. NMR studies showed that the major conformer of N -methyl- N -(3-thienyl)amide in solution is the E- form ( cis form), as is the case for N -methylacetamide. For N -aryl- N -(3-thienyl)amides bearing an N -phenyl moiety, the major conformers differ depending on not only the relative π-electron density of the N -aryl moiety, but also its size. X-ray analysis showed that their solid-state conformational preferences were similar to those in solution. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) studies of acid-induced conformational switching ( trans / cis isomerization) of N , N -diarylamides bearing a pyridine moiety indicated that the trans / cis conformational preference of these amides is dependent on the relative π-electron densities of the two N -aromatic parts, and can be controlled by protonation or deprotonation of pyridine. [ABSTRACT FROM AUTHOR]

We have investigated acid- and base-induced conformational alterations of N -aryl- N -troponyl amides containing an electron-donating group on the phenyl ring. NMR spectral studies indicated that the E / Z conformational preferences of these amides can be reversibly controlled by pH-dependent protonation or deprotonation of the tropolone moiety. Thus, these compounds have potential applications as acid/base-controllable molecular switches. [ABSTRACT FROM AUTHOR]

Amide oligomers composed of pyridine-2-carboxamide as the repeating unit were synthesized in a stepwise manner and their structures were examined by means of 1 H NMR, NOE measurements, and DFT calculations. All the synthesized oligomers adopted a folded conformation, but became partially unfolded at the C-terminal upon addition of acid. A characteristic long-range hydrogen bond, which stabilizes local folding, was present in oligomers with a long main chain. [ABSTRACT FROM AUTHOR]

Strategic use of hard gold(III) and soft gold(I) catalysts provides facile access to two types of 2-substituted piperidines from propargylic alcohols. Thus, heating propargylic alcohols in the presence of AuBr 3 results in cyclization to furnish piperidines having an acetylenic moiety, due to activation of the propargylic hydroxyl group by coordination of gold(III). On the other hand, the catalyst [Ph 3 PAuNTf 2 ] 2 PhMe induces Meyer–Schuster rearrangement of propargylic alcohols to give α,β-unsaturated ketones, which undergo intramolecular aza-Michael addition to afford piperidines bearing a carbonyl group, due to activation of the triple bond by coordination of gold(I). [ABSTRACT FROM AUTHOR]

Perpendicular recording media technology faces limitation in the writability of media with high anisotropy. Therefore, alternative methods are sought to overcome this problem. Heat-assisted magnetic recording may give rise to high areal densities, but the technological process will take time. We have studied methods to improve the writability in perpendicular recording media using crystalline soft underlayer (C-SUL) materials with fcc(111) texture. One of the recording media designs consists of a simple insertion of C-SUL material between the nonmagnetic intermediate layers, thus providing a path for magnetic flux during the writing. In the alternative methods, part of the nonmagnetic intermediate layer material was replaced with C-SUL material. Overwrite improvement was observed in both the cases, indicating that the C-SUL material will play a major role in improving writability in recording media. [ABSTRACT FROM AUTHOR]

Abstract: The conformation of N-phenylbenzohydroxamic acid has been reported to change depending on the solvent properties. Here, we newly synthesized N-phenylbenzohydroxamic acid derivative, which contains two pyrene moieties separated from the phenyl rings by ethylene linkers. It showed solvent-dependent conformational change, and its fluorescence was also solvent-dependent, that is, only monomer fluorescence of pyrene was observed in DMSO or DMF, whereas the excimer fluorescence was observed in CH2Cl2 or CHCl3. Thus, the structural characteristics could be converted to fluorescence change as output, which would be a good candidate as a fluorescent sensor. [Copyright &y& Elsevier]

[Display omitted] • The crystal structures of N , N -diarylamides bearing two azulenes were analyzed. • The linkage position on azulene influences the dihedral angle to the amide plane. • The N -(2-azulenyl) group is almost coplanar with the amide plane. N , N -Diarylacetamides bearing two azulene rings on the amide nitrogen were synthesized and their crystal structures were determined. The dihedral angle between the amide plane and the aryl ring located on the same side as the amide oxygen atom is influenced by the position of linkage of the aromatic ring to the nitrogen atom, and a 2-azulenyl group located on the same side as amide oxygen atom tends to be coplanar with the amide plane. This feature may be useful in the design of molecular devices and supramolecules. [ABSTRACT FROM AUTHOR]

Ethyl glyoxylate O-tert-butyldimethylsilyloxime (8), on treatment with 2.2 equiv of BF3·OEt2, generated N-boranonitrone E, which underwent intermolecular cycloaddition with alkenes 18 to afford isoxazolidines 19 in moderate to high yields. The cycloaddition of N-boranonitrone E with most of the alkenes gave 3,5-trans isoxazolidines as the major isomers via a concerted mechanism. However, in the case of 1-methylated cyclic alkenes (18j and 18l), the cycloaddition surprisingly furnished the 3,3a-cis-cycloadducts (19j and 19l) as major isomers. A possible explanation is that the reaction of 1-methylated cyclic alkenes proceeds mainly via a stepwise mechanism. This reaction of terminal alkenes is very useful for synthesis of 1,3-anti aminoalcohol derivatives by reductive cleavage of an N-O bond. [ABSTRACT FROM AUTHOR]

Abstract: Uncatalyzed cycloaddition of α-alkoxycarbonylnitrones 1 with vinyl ethers 7 gave mixtures of cis- and trans-cycloadducts 8, whereas Eu(fod)3-catalyzed cycloaddition of 1 with 7 gave the trans-cycloadducts trans-8 in a highly stereoselective manner. NMR studies indicated that Eu(fod)3 selectively activated (Z)-nitrones (Z)-1 in E,Z-equilibrium mixtures of nitrones 1. In contrast, the reaction of 1 with allyl alcohols 12 in the presence of Eu(fod)3 resulted in sequential transesterification and intramolecular cycloaddition to give intramolecular cycloadducts 13. [Copyright &y& Elsevier]

We developed a simple method for the direct synthesis of 2,2′-binaphthoquinones, utilizing oxidative dimerization via electron donor–acceptor complex formation of 1-naphthols with SnCl4 in the presence of dioxygen. This oxidation involves a catalytic cycle of SnCl4, and the reaction mechanism is discussed. As an application of this method to natural products synthesis, we describe facile biomimetic syntheses of the binaphthoquinones 3,3′-bijuglone, 3,3′-biplumbagin and elliptinone. [Copyright &y& Elsevier]