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A Lewis acid promoted tandem reaction of intramolecular [3+2] cycloaddition/O−H insertion/ester exchange of cyclopropanes with diazocarbonyls is reported to synthesize fused‐oxa‐[n.2.1] skeletons, which tolerates both aryl and alkyl diazocarbonyl substrates. A wide variety of fused‐oxa‐[n.2.1] skeletons were efficiently constructed. [ABSTRACT FROM AUTHOR]

Flexible microcircuits are developing rapidly with the trends of miniaturization and foldability in modern electronic products. The chemical growth welding technique of silver seeds offers several advantages, including compatibility with a wide range of substrates, ease of operation, and room temperature growth, making it a promising method for use in the manufacturing of flexible electronics. In this paper, we demonstrated a feasible solution based on silver seeds and the chemical welding process of copper at near room temperature. The growth of copper microcircuits was directly determined by the size and distribution of silver seeds. Seeding parameters for preparing long copper microcircuits were optimized, and two types of possible defects in the as-prepared copper microcircuits were analyzed. Based on the optimized parameters, patterned fine copper microcircuits and large-area copper wires were prepared, and the conductivity and fatigue resistance were verified. [ABSTRACT FROM AUTHOR]

The asymmetric synthesis of Szántay's amine (+)-2, the pivotal precursor for direct access to (+)-cycloclavine (1), is described for the first time in eleven steps with 19.7% overall yield from the commercially available 4-bromoindole. The strategy features an asymmetric induction by Ellman's sulfinimine and rhodium-catalysed isomerization of the C=C bond. [ABSTRACT FROM AUTHOR]

An enantioselective tandem Michael addition/cyclization reaction between trisubstituted 2-nitro-1,3-enynes and cyclic 1,3-diketones catalyzed by a chiral organosquaramide catalyst in the presence of Ag2CO3 was developed. The chiral functionalized chromene products could be obtained in good yield and in 80-99% enantiomeric excess. The structures and absolute configurations of some of the products were confirmed by X-ray crystallographic analysis. [ABSTRACT FROM AUTHOR]

The ionization processes of NH3 molecule are studied by photoelectron velocity map imaging technique in a linearly polarized 400-nm femtosecond laser field. The two-dimensional photoelectron images from ammonia molecules under different laser intensities are obtained. In the slow electron region, the values of kinetic energy of photoelectrons corresponding to peaks 1, 2, 3, and 4 are 0.27, 0.86, 1.16, and 1.6 eV, respectively. With both the kinetic energy and angular distribution of photoelectrons from NH3 molecules, we can confirm that the two-photon excited intermediate Rydberg state is A∼1 () state for photoelectron peaks 2, 3, 4, and the three peaks are marked as 1223 (2 + 2), 1123 (2 + 2), and 1023 (2 + 2) multi-photon processes, respectively. Then, peak 1 is found by adding a hexapole between the source chamber and the detection chamber to realize the rotational state selection and beam focusing. Peak 1 is labeled as the 1323 (3 + 1) multi-photon process through the intermediate Rydberg state. The phenomena of channel switching are found in the slow electron kinetic energy distributions. Our calculations and experimental results indicate that the stretching vibrational mode of ammonia molecules varies with channels, while the umbrella vibration does not. In addition, we consider and discuss the ac-Stark effect in a strong laser field. Peaks 5 and 6 are marked as (2 + 2 + 1) and (2 + 2 + 2) above threshold ionization processes in the fast electron region. [ABSTRACT FROM AUTHOR]

The above-threshold ionization process of ammonia molecules induced by a femtosecond laser field at 800 nm is studied in the intensity range from 1.6 Ă— 1013 to 5.7 Ă— 1013 W/cm2. Channel switching under different laser intensities is observed and identified in the photoelectron kinetic energy spectra of ammonia. Based on the photoelectron kinetic energy distributions and the photoelectron angular distributions, the characteristic peaks observed are exclusively assigned to the multiphoton resonance through certain intermediate states, followed by multiphoton above-threshold ionization. [ABSTRACT FROM AUTHOR]

Ubiquitin-conjugating enzyme E2S (UBE2S), an important E2 enzyme in the process of ubiquitination, has exhibited oncogenic activities in various malignant tumors. However, it remains unknown whether UBE2S plays a role in urinary bladder cancer (UBC) development. In the current study, our data confirmed UBE2S upregulation in UBC. In vitro and in vivo experiments demonstrated that UBE2S knockdown resulted in attenuated proliferation and enhanced apoptosis, which was inverse to the phenotypes with UBE2S overexpression. Gain and loss of function assays confirmed that UBE2S exerts oncogenic activities in UBC by mediating the activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway. Furthermore, we discovered that this UBE2S-modulated carcinogenic mechanism was in the consequence of directly targeting tuberous sclerosis 1 (TSC1), which is the upstream inhibitor of mTOR signaling for ubiquitous degradation. Taken together, this study demonstrated that UBE2S is a carcinogen in UBC and promotes UBC progression by ubiquitously degrading TSC1. This consequently mediates the activation of the mTOR pathway, suggesting a potential therapeutic regimen for UBC by targeting the newly identified UBE2S/TSC1/mTOR axis. • The expression of UBE2S is significantly upregulated in UBCs. • UBE2S exerts oncogenic activities in UBCs via enhancing proliferation and attenuating apoptosis. • UBE2S mediates the degration of TSC1 via ubiquitination to activate mTOR pathway. • UBE2S exerts oncogenic activities by ubiquitously degrading TSC1. [ABSTRACT FROM AUTHOR]

Reported herein is the construction of chiral aza‐[n.2.1] skeletons by separable epimers of intramolecular [3+2] cross cycloaddition of cyclopropane 1,1‐diesters with chiral sulfinylimines. The epimer products can be separated by silica gel column chromatography. [ABSTRACT FROM AUTHOR]