PtI2-catalyzed tandem 3,3-rearrangement/Nazarov reaction of arylpropargylic esters: synthesis of indanone derivatives

An efficient PtI(2)-catalyzed tandem reaction of arylpropargylic esters, involving 3,3-rearrangement and Nazarov reaction, has been developed to produce 3-substituted and 3,3-disubstituted indanone derivatives. This approach provided a pathway to the synthesis of indanone skeletons in natural products.     

Concise total synthesis of (±)-dasyscyphin D

The first and efficient total synthesis of (±)-dasyscyphin D was achieved in 9 steps with 22.6% overall yield. The key steps involved a PtCl(2)-catalyzed pentannulation reaction and acid-catalyzed double Robinson annulations.     

Absorbable phenylpropenoyl sucroses from Polygala tenuifolia

Three phenylpropenoyl sucroses--sibiricose A5, A6 and 3',6-disinapoyl sucrose--were isolated from the 30% EtOH extract of Polygala tenuifolia, which displayed antidepressant-like action. HPLC analysis indicated that the three phenylpropenoyl sucroses could be absorbed into serum. From the serum pharmacochemistry point of view, these three phenylpropenoyl sucroses might prevent or relieve depression.     

Effects of electric field annealing on the interface diffusion of Cu/Ta/Si stacks

In the present paper, the effects of electric field annealing on interface diffusion of Cu/Ta/Si stacks were studied by means of XRD, XPS and TEM. The barrier property of Ta films was evaluated based on the diffusion of Cu atoms. It was found that the external electric field accelerates the diffusion of Cu atoms through Cu/Ta/Si interfaces during annealing. With the increment of annealing temperature, the effect of the electric field upon the atomic diffusion becomes more significant. The mechanism of accelerated interface diffusion is suggested and the failure of Ta barrier layer is discussed based on the mobility of vacancies and Cu atoms inside Cu/Ta/Si stacks caused by the electric field.     

Studies on the Phase Behavior of Beta‐cypermethrion Microemulsion

The phase behavior of the system of surfactant SAA [0203B, nonionic surfactant 700# and methanol (weight ratio=6∶1∶1)]/mixed oil [beta‐cypermethrion, dimethyl benzene and cyclohexanone (weight ratio=2∶2∶1,or 0∶2∶1)]/water [distilled water (0 mg/L), or standard water (342 mg/L), or ultra‐hard water (500 mg/L)] has been studied in a pseudoternary phase diagram at 25 ± 1°C. Our results indicated that the isotropic monophasic area in the phase diagrams decreased significantly as the beta‐cypermethrion was added in the oil phase. In an attempt to the microemulsion electrical condectivity can be define regions corresponding to three structure states W/O, B.C., and O/W type in the microemulsion domain. The influence of beta‐cypermethrion on their regions sequences B.C. > O/W?W/O type. This work will be beneficial to improving the quality of beta‐cypermethrion microemulsion and make it more competitive in the market.     

Preparation and characterization of side chain cholesteric liquid crystalline polysiloxanes containing two chiral groups

A series of liquid crystalline (LC) polysiloxanes containing diosgeninyl and menthyl groups (from monomers M ₁ and M ₂, respectively) were synthesized. The chemical structures of the monomers and polymers obtained were confirmed by elemental analysis, Fourier transform infrared spectroscopy, proton NMR and carbon‐13 NMR. The LC properties were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction. Monomer M ₁ showed cholesteric oily‐streak and spiral textures. Copolymers P ₂–P ₅ exhibited cholesteric phases. With increasing concentration of M ₂ units, the glass transition and clearing temperatures decreased. Experimental results demonstrated that a flexible polymer backbone and a long flexible spacer tended to favour a lower glass transition temperature, higher thermal stability, and wider mesophase temperature range.     

Dihydroisocoumarin derivatives with antifouling activities from a gorgonian-derived Eurotium sp. fungus

Five pairs of new dihydroisocoumarin enantiomers, (±)-eurotiumides A–E, and two related racemates, (±)-eurotiumides F and G, were isolated from a gorgonian-derived fungus, Eurotium sp. XS-200900E6. The enantiomeric separations for (±)-eurotiumides A–E were achieved by chiral-HPLC, and their absolute configurations were determined by ECD spectra. All of the isolated compounds are rare dihydroisocoumarin derivatives with a methoxy at C-4. (+)- And (−)-eurotiumides B and D with cis configurations of H-3/H-4 exhibited potent antifouling activities against the larval settlement of the barnacle Balanus amphitrite with the EC₅₀ values ranging from 0.7 to 2.3 μg/mL, and displayed high therapeutic ratios (LC₅₀/EC₅₀ >15). The tested compounds also showed extensive antibacterial activities. It was the first report of antifouling activities for dihydroisocoumarin derivatives.     

A New Polyketide from the Mangrove Endophytic Fungus Penicillium sp. sk14JW2P

Two polyketides were isolated from the mangrove endophytic fungus, Penicillium sp. sk14JW2P, and one derivative with a modified structure. The structures were elucidated by spectroscopic analyses, the structure of the compound 1 was further confirmed by single‐crystal X‐ray diffraction, and its absolute configuration was determined. Compound 1 and 2 showed acetylcholinesterase (AchE) inhibitory activities with IC₅₀ values of 12±0.3 and 79±2 nM , respectively.