Simple preparation of phenylpropenoid β-d-glucopyranoside congeners by Mizoroki-Heck type reaction using organoboron reagents

Palladium(II)-catalyzed carbon-carbon bond formation between allyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside (3) and arylboronic acid congeners gave the corresponding cinnamyl 2,3,4,6-tetra-O-acetyl- β-d-glucopyranosides (4a-m) in good yield. Among them, coupling products 4a-m were converted to not only the naturally occurring phenylpropenoid β-d-glucopyranoside analogues (1a-e) but also the unnaturally ones (1f-m).     

Total synthesis of (S)-(+)-curcudiol, and (S)-(+)- and (R)-(-)-curcuphenol.

A highly enantioselective synthesis of the versatile chiral synthons possessing one stereogenic center, (S)- and (R)-4-aryl-5-hydroxy-(2E)-pentenoate (3) was achieved based on the enzymatic reaction of (+/-)-3 with commercially available lipases MY-30 or OF-360 from Candida rugosa. Application of (S)-3 and (R)-3 to the total syntheses of(S)-curcuphenol (1), (S)-curcudiol (2), and (R)-curcuphenol (1), respectively, is described.     

Recognition of Multiple Methyl Groups on Aromatic Rings by a Polyaromatic Cavity

The methyl group is a small substituent, usually showing relatively weak or no interactions with other functional groups and metal ions. Herein, we present the recognition of the number of methyl groups on synthetic and natural aromatic compounds (i.e., benzene and xanthine derivatives, respectively) by the 1 nm‐sized polyaromatic cavity of a coordination capsule in water. Detailed competitive encapsulation experiments as well as X‐ray crystallographic analysis revealed that multiple guest–host CH₃–polyaromatic interactions in the confined nanospace are key driving forces for the high selectivity.     

Electrochemical determination of nitrite using a gold nanoparticles-modified glassy carbon electrode prepared by the seed-mediated growth technique.

Seed-mediated growth of gold nanoparticles on glassy carbon (GC) surfaces was developed. The field emission scanning electron microscopy (FE-SEM) and electrochemical characterization confirmed the effective attachment of gold nanoparticles on GC surface with such a wet-chemical method. The as-prepared gold nanoparticles attached glassy carbon electrode (Au/GCE) presented excellent catalytic ability toward the oxidation of nitrite. Compared with bare GCE and planar gold electrode, the Au/GCE obviously decreased the overpotential of nitrite oxidation and improved the peak current. The catalytic current was found to be linearly proportional to the nitrite concentration in the range of 1 x 10(-5) - 5 x 10(-3) M, with a detection limit of 2.4 x 10(-6) M. The Au/GCE was successfully applied to the electrochemical determination of nitrite in a real wastewater sample, showing excellent stability and anti-interference ability.     

A new method for the conversion of allyl alcohol into pi-allyl species promoted by nucleophilic interaction with a CO ligand

Upon treatment with an iridium carbonyl complex, [(PN)Ir(CO)2]+, allyl alcohol can be smoothly converted into pi-allyliridium species at ambient temperature via nucleophilic interaction of the alcohol with a CO ligand followed by C(allyl)-O bond cleavage in the resultant protonated allyloxycarbonyl intermediate.     

Imaging findings of solitary fibrous tumor of the prostate: a case report

The imaging findings of a solitary fibrous tumor of the prostate are presented. A 35-year-old male presented with urinary retention and was found on transrectal ultrasonography to have a hypoechoic tumor of the prostate, measuring 5.5 cm in size. Magnetic resonance imaging on, the tumor showed low signal intensity on T1-weighted images and heterogeneous mixed signal intensity on T2-weighted images. Gadolinium-enhanced dynamic study showed gradual enhancement from the periphery to the center, and the enhancement is sustained. On immunohistochemistry, the spindle cells of the tumor showed positive staining for CD34 and bcl-2. Although the tumor was labeled as a low-grade malignancy on account of a low mitotic index (MIB-1 index) of about 5%, the patient developed local recurrence of the tumor with bladder wall invasion 12 months later.     

High-dimensional Edgeworth expansion of a test statistic on independence and its error bound

In this paper, we calculate Edgeworth expansion of a test statistic on independence when some of the parameters are large, and simulate the goodness of fit of its approximation. We also calculate an error bound for Edgeworth expansion. Some tables of the error bound are given, which show that the derived bound is sufficiently small for practical use.     

Synthesis and spectroscopic study of phenylene-(poly)ethynylenes substituted by amino or amino/cyano groups at terminal(s): electronic effect of cyano group on charge-transfer excitation of acetylenic π-systems

To gain insight into substituent electronic effect on charge-transfer excitation of acetylenic π-systems, phenylene-(poly)ethynylenes substituted by Ph₂N or Ph₂N/cyano groups were synthesized by combination of Sonogashira coupling and double elimination protocol of β-substituted sulfones. These substituted phenyleneethynylenes showed large molar absorption coefficients ?, and emitted strong fluorescence upon UV light irradiation. Phenylene-(poly)ethynylenes, which involve butadiyne or hexatriyne motifs, emitted fluorescence in remarkably lower fluorescence quantum yields Φ_F as their polyethynylene motifs -(CC)_n- expanded. The drastic decrease of fluorescence quantum yields Φ_F were explained in terms of increasing nonradiative reaction rate constants k_nr, which had been determined by the corresponding fluorescence quantum yields Φ_F and lifetime values τ. The emission underwent a large bathochromic shift in polar solvents because the charge-separated excited state is more stabilized than the ground state. Comparison of slope values ρ in Lippert/Mataga plot for the Ph₂N and Ph₂N/cyano-substituted phenylene-(poly)ethynylenes revealed that the latter underwent large change of dipole moments upon photo-excitation although highly expanded acetylenic π-systems with cyano group did little.     

A new synthetic route to 7 α-methoxycephalosporins

Treatment of 7β-(2,2,3-trihaloalkylideneamino) cephalosporins with excess methanol in the presence of acid scavenger gave 7β-(2-haloalk-2-enylideneamino)-7α-methoxycephalosporins.