Visible-light-promoted radical alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester: Synthesis of oxazolines

An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.     

Effect of external electric field on the terahertz transmission characteristics of electrolyte solutions

We fabricated a microfluidic chip with simple structure and good sealing performance, and studied the influence of the electric field on THz absorption intensity of liquid samples treated at different times by using THz time domain spectroscopy system. The tested liquids were deionised water and CuSO₄, CuCl₂, NaHCO₃, Na₂CO₃ and NaCl solutions. The transmission intensity of the THz wave increases as the standing time of the electrolyte solution in the electric field increases. The applied electric field alters the dipole moment of water molecules in the electrolyte solution, which affects the vibration and rotation of the whole water molecules, breaks the hydrogen bonds in the water, increases the number of single water molecules and leads to the enhancement of the THz transmission spectrum.     

Artematrovirenolides A—D and Artematrolides S—Z,Sesquiterpenoid Dimers with Cytotoxicity against Three Hepatoma Cell Lines from Artemisia atrovirens

Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided approach.Their structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD calculations.Structurally,all compounds are presumably formed via[4+2]cycloaddition involving three connecting model.Compounds 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also proposed.Compounds 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/L.Interestingly,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,sorafenib.This investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study.     

Yb:CaF2–YF3 transparent ceramics ultrafast laser at dual gain lines

Yb³⁺:CaF₂-YF₃ transparent ceramics with excellent optical quality was successfully fabricated by hot-pressed method. Pulsed laser properties of this ceramics were investigated for the first time. Laser diode (LD) was applied as the pump source to generate a dual-wavelength mode-locked (ML) laser. The maximum average output power was 310 mW, which represents the highest output power of ultrafast calcium fluoride ceramic laser. The spectrum separated at 1048.9 nm and 1049.7 nm with a total pulse duration of 8.9 ps. The interval period between the beating signals was about 4.3 ps, corresponding to a 0.23 THz beat pulse repetition rate. These results demonstrate its potential in producing dual-wavelength ultrashort pulses. These Yb³⁺:CaF₂-YF₃ ceramics with low-cost and short-preparation period are ideal candidate materials for ultrafast lasers.     

Unidirectional acoustic metamaterials based on nonadiabatic holonomic quantum transformations

Nonadiabatic holonomic quantum transformations(NHQTs)have attracted wide attention and have been applied in many aspects of quantum computation,whereas related research is usually limited to the field of quantum physics.Here we bring NHQTs into constructing a unidirectional acoustic metamaterial(UDAM)for shaping classical beams.The UDAM is made up of an array of three-waveguide couplers,where the propagation of acoustic waves mimics the evolution of NHQTs.The excellent agreement among analytical predictions,numerical simulations,and experimental measurements confirms the great applicability of NHQTs in acoustic metamaterial engineering.The present work extends research on NHQTs from quantum physics to the field of classical waves for designing metamaterials with simple structures and may pave a new way to design UDAMs that would be of potential applications in acoustic isolation,communication,and stealth.     

TPE based aggregation induced emission fluorescent sensors for viscosity of liquid and mechanical properties of hydrogel

Two amphiphilic TPE E/Z isomers with aggregation induced emission(AIE) property have been synthesized and characterized. The logarithmic fluorescent intensity of the two molecules was in positive relationship with logarithmic viscosity of liquid. To note, the Z-TPE isomer exhibited more sensitivity in the viscosity of liquid sensing in comparison with the corresponding E-TPE counterpart(around 1.80 folds).Furthermore, two molecules could be used as fluorescent sensors for mechanical properties(v...     

Construction Theory of Function on Local Fields

We establish the construction theory of function based upon a local field K p as underlying space. By virture of the concept of pseudo-differential operator, we introduce "fractal calculus"(or, p-type calculus, or, Gibbs-Butzer calculus). Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D( Kp) and locally compact group K+p(= Kp), so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type,and equivalent approximation theorems on the H ?lder-type space Cσ(Kp), σ 0, are proved; then the equivalent approximation theorem on Sobolev-type space Wrσ(Kp),σ≥ 0, 1 ≤ r +∞, is shown.     

Endogenous peroxynitrite activated fluorescent probe for revealing anti-tuberculosis drug induced hepatotoxicity

Pyrazinamide(PZA), isoniazid(INH) and rifampicin(RFP) are all commonly used anti-tuberculosis drugs in clinical practice, and long-term medication may cause severe liver damage and toxicity. The level of peroxynitrite(ONOO–) generated in liver has long been regarded as a biomarker for the prediction and measurement of drug-induced liver injury(DILI). In this article, we constructed a BODIPY-based fluorescent probe(BDP-Py+) that enabled quickly and sensitively detect and image ONOO–in vivo. Utili...     

Solvent free synthesis of trifluoromethyl tertiary alcohols by cross Aldol reaction

Exceedingly fast preparation of trifluoromethyl tertiary alcohols has been accomplished from methyl ketones and trifluoromethyl ketones under solvent free conditions by cross Aldol reaction. The reaction was achieved in the presence of common inorganic base by grinding method at ambient temperature to give β-trifluoromethyl-β-hydroxyl ketones in high yields (up to 95%).