Rhodium(III)-catalyzed C4-amidation of indole-oximes with dioxazolones via C-H activation.

A novel method for the Rh(iii)-catalyzed oxime-directed C-H amidation of indoles with dioxazolones has been developed. This strategy provides an exclusive site selectivity and the directing group can be easily removed. This transformation features a wide substrate scope, good functional group tolerance and excellent yields, and may serve as a significant tool to construct structurally diverse indole derivatives for the screening of potential pharmaceuticals in the future.

Copper-mediated direct thiolation of aryl C-H bonds with disulfides.

An efficient copper-mediated ortho-C(sp2)-H thiolation of aromatic amides directed by a novel directing group [4-chloro-2-(1H-pyrazol-1-yl)phenyl]amine has been developed without the need of other additives or oxidants, allowing for an increased usefulness. With the high compatibility of sterically demanding substrates, this reaction is scalable and can tolerate a wide scope of functional groups to provide alkyl and aryl thioethers in good to excellent yields (up to 93%). Furthermore, the protocol has been successfully implemented for the selenylation as well.

Palladium-catalyzed direct mono-aroylation of O-arylmethyl and aryl-substituted acetoxime ethers.

An efficient palladium-catalyzed ortho-aroylation of O-arylmethyl and aryl-substituted acetoxime ethers has been developed; this method has high mono-site selectivity and does not require exogenous ligands. Under the direction of a simple exo-acetoxime auxiliary, a broad scope of masked arylmethyl alcohols and phenols as well as various aromatic aldehydes are compatible with this transformation, which probably follows a mechanistic pathway involving a six- or five-membered exo-cyclopalladated intermediate. The strategy can be expediently adopted to prepare synthetically valuable 1H-benzo[d][1,2]oxazines and benzo[d]isoxazoles. The directing group can be easily removed from the products to afford the functionalized diaryl ketones.

[Spectra line profile and vibrational temperature of dot and line discharge in a dielectric barrier discharge].

The emission spectrum line shift and vibrational temperature of dot and line discharges, which coexist in argon/air dielectric barrier discharge, were measured and compared. Emission spectral lines of ArI (2P2 --> 1S5) and the N2 second positive band system (C 3pi(u) --> B 3pi(g)) were used to measure the spectrum line shift and the vibrational temperature respectively. It was found that the spectrum line shift of the dot discharge channel is larger than that of the line discharge channel, indicating that the former has high electron density compared to the latter. While the vibrational temperature of the dot discharge channel is lower than that of the line discharge channel.

[Study on spectral line profile of different types of filaments in dielectric barrier discharge].

The variations of width and shifts of Ar I (2P2 --> 1S(5)) spectral line emitted from two types of filaments, whose diameters and states are different, in argon/air dielectric barrier discharge with the change in air content were researched for the first time. In order to measure the wavelength shift, Ar I (2P2 --> 1S(5)) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. Regular arrangements of static wide filaments (static big dots) and moving thin filaments (reciprocating moving small dots whose traces are lines) were obtained in discharge at atmospheric pressure when the air content was in the range of 0.4%-4%. The variations of width and shifts of Ar I (2P2 --> 1S(5)) spectral line emitted from the big and small dots with the change in air content were measured respectively. It was found that they all increase with the increasing in air content. The width and shift of small dot are bigger than those of the big dot at any air content. The difference between the former and the latter decreases with the increase in air content firstly and remains basically unchanged after the air content reaches up to 1%.

[Study on plasma parameters in diffuse discharge with semispherical electrod by optical emission spectrum].

The diffuse discharge plasma in air was observed in a dielectric barrier discharge with two semispherical water electrodes. The variations of vibration temperature, rotation temperature, and average electron energy as the function of the applied voltage were studied by emission spectroscopy. The vibration temperature and the rotation temperature were calculated through the second positive band system (C3Pi(u)-->B3Pi(g)) of N2+ and the first negative band system (B2 Sigma(u+)-->Chi2Sigma(g+)) of N(2+) respectively. The average electron energy was studied by intensity ratio of 391.4 and 337.1 nm. It was found that the rotation temperature increases with the applied voltage increasing, while the vibration temperature and the electron energy decrease.

[Spectra line profile and vibrational temperature of bright dot and dark dot discharge in a dielectric barrier discharge].

The emission spectrum line shift and vibrational temperature of the bright dot and dark dot discharges, which are observed in the argon and air dielectric barrier discharge at high temperature for the first time were measured and compared. The line shift of the spectral line of the Ar I (2P2-->1S5) is measured and the vibrational temperature was calculated using by the emission spectral lines of the N2 second positive band system (C3Pi(u)-->B3Pi(g)). The results show that the spectrum line shift of the bright dot discharge channel is larger than that of the dark dot channel, which indicates that the former has higher electron density compared to the latter, and the vibrational temperature of the dark dot discharge channel is higher than that of the bright dot discharge channel.

[Study on spatial distribution of electron energy in hollowneedle-plate dielectric barrier discharge].

In the present work, the spatial distributions of spectrum intensity of molecule and atom in the plasma generated in hollowneedle-plate discharge in atmosphere were measured, and the spatial distribution of electron energy in plasma was analyzed. A plasma about 3 cm long is generated by using a hollowneedle-plate discharge device. By collecting optical emission spectrum from 300 to 800 nm, it was found that the spectrum consists of strong Ar I lines, strong second positive band system of N2, and weak OI line. The spatial distributions of spectrum intensity of Ar I (696.54, 763.51, 772.42, and 794.82 nm), band N2 (337.1, 357.6, and 380.4 nm), and OI 777.2 nm were measured. The Ar I lines decreased gradually from the arc root. The N2 lines increased gradually from the arc root and declined when they reached a maximum at 12 mm away from the arc root. The intensity of OI increased from the arc root and declined when it reached a maximum at 6 mm away from the arc root. The spatial distribution of electron energy in plasma was analyzed qualitatively from the spatial distribution of spectrum intensity given above. It was found that the electrons located at 6 mm away from the are root have high energy, while they have low energy at arc tip.

[Study of spectral line profile in a slot microplasma].

The variations of width and shift of Ar I (2P2 --> 1S5) spectral line with discharge parameters were studied in a slot microplasma. In order to measure the wavelength shift, the Ar I (2P2 --> 1S5) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. With the gas pressure increasing in the range of 1 x 10(4) - 6 x 10(4) Pa, the width and shift of Ar I (2P2 --> 1S5) spectral line were measured in argon (99.92%)/air discharge. It was found that both the width and the shift of Ar I (2P2 --> 1S5) spectral line increase linearly with the increase in gas pressure, indicating that the electron density increases with the increase in gas pressure. In addition, the width and the shift of Ar I (2P2 --> 1S5) spectral line at gas gap width of 100 and 300 microm were measured for comparison. It was found that both increase with the increase in gas gap width, which indicates that the electron density in the slot microplasma increases with the increase in gas gap width.

[Spectral analysis of different boundary discharge domain in dielectric barrier discharge].

Different discharge modes in different boundary discharge domains at the same experimental condition are observed in argon/air mixture in a dielectric barrier discharge system with two large diameter water electrodes. Regular patterns and random filaments are formed in the closed square boundary and the semiopen domain respectively. It is found that the relatively intensity of the several higher excitation energy spectral lines such as 696.5, 727.3, 750.4 and 772.4 nm increases with the applied voltage in the closed boundary domain while decreases in the semiopen domain. Results show that the electron average energy in the closed boundary is higher than that in the semiopen domain and the difference of the electron average energy increases with the applied voltage. The results of molecular vibration temperature estimated by the second positive spectrum of N2 molecular indicate that the vibration temperature increases with the applied voltage in the closed boundary and decreases with the applied voltage in the semiopen boundary domain.

Parallel approach for solution-phase synthesis of 2-quinoxalinol analogues and their inhibition of LPS-induced TNF-alpha release on mouse macrophages in vitro.

A parallel solution-phase synthesis of 2-quinoxalinol analogues is described. The key step-simultaneous reductions of m-Ar(NO2)2 to m-Ar(NH2)2 was investigated extensively. We obtained preliminary pharmacological activity of those analogues for the inhibition of LPS-induced TNF-alpha release on mouse macrophage in vitro. Two compounds revealed inhibitory activity, with IC50 values of 0.40 microM (7-amino-6-[(3-methoxypropyl)amino]-3-methyl-2-quinoxalinol) and 2.2 microM (7-amino-6-[(3-butoxypropyl)amino]-3-methyl-2-quinoxalinol), respectively.