Facile Synthesis of 3-Substituted Thiazolo[2,3-α]tetrahydroisoquinolines.

It was found that 4-hydroxy-2-butenoic ester (11) could not react with 3,4-dihydro-isoquinoline (4a). Individual addition reactions of γ-mercapto-α,ß-unsaturated esters (18) and -unsaturated amide (19) with 3,4-dihydroisoquinolines (4) were carried out under appropriate conditions to provide the corresponding thiazolo[2,3-α]isoquinoline derivatives with good yields (up to 87%) and significant diastereomeric selectivity. The mechanism of the crucial reaction was discussed.

Total Synthesis of (+)-Antrocin and Its Diastereomer and Clarification of the Absolute Stereochemistry of (-)-Antrocin.

Using 2,2-dimethyl cyclohexanone as the starting compound, (+)-antrocin and its diastereomer have been synthesized. The absolute stereochemistry of (-)-antrocin, a natural sesqui-terpenoid and an antagonist in some types of cancer cells, was clarified using the character data of (+)-antrocin. The synthetic procedure involved two key steps: (1) the reaction of vinyl magnesium bromide with 2,2-dimethyl-6-t-butyl-dimethyl-silyoxy-methyl-1-cyclo-hexanone to give a vinyl cyclohexanol derivative and (2) a highly stereoselective intramolecular Diels-Alder (IMDA) reaction of the camphanate-containing triene intermediate. The relative energy levels of the possible transition states of the IMDA reaction of the camphanate-containing triene were obtained from density functional theory calculations, proving the stereospecific formation of the target molecule.

Inhibition of pentraxin 3 in glioma cells impairs proliferation and invasion in vitro and in vivo.

Pentraxin 3 (PTX3) is an inflammatory molecule that is involved in immune responses, inflammation, and cancer. Recent evidence suggests that PTX3 plays a critical role in tumor progression; however, its impact on the biological function of gliomas remains unknown. In the present study, immunohistochemical staining showed that patients with high-grade gliomas exhibited increased expression levels of PTX3 compared to those with low-grade gliomas (P < 0.001). Furthermore, knockdown of PTX3 in GBM8401 cells inhibits proliferation, increases p21 protein levels, and decreases cyclin D1 protein levels, resulting in cell cycle arrest at the G0/G1 phase. In addition, knockdown of PTX3 significantly decreases GBM8401 cell migration and invasion through the downregulation of matrix metalloproteinase-1 and -2 (MMP-1 and MMP-2) expression. In a GBM8401 xenograft animal model, PTX3 knockdown decreases tumor growth in vivo. In conclusion, PTX3 plays an important role in glioma cell proliferation and invasion, and may thus serve as a novel potential therapeutic target in the treatment of gliomas.

Pyromellitic dithioimides: thionation improves air-stability and electron mobility of N-type organic field-effect transistors.

Thionation and fluorination of pyromellitic diimides (PyDIs) increased the electron mobility and on/off ratio of the original diimides by two orders of magnitude and improved the threshold voltage and air-stability of diimide compounds.

Linear oligoarylamines: electrochemical, EPR, and computational studies of their oxidative states.

A series of straight-chain oligoarylamines were synthesized and examined by electrochemical, spectroelectrochemical, electron paramagnetic resonance techniques, and density functional theory (DFT) calculation. Depending on their electrochemical characteristics, these oligoarylamines were classified into two groups: one containing an odd number and the other an even number of redox centers. In the systems with odd redox centers (N1, N3, and N5), each oxidation was associated with the loss of one electron. As for the systems with even redox centers (N2, N4, and N6), oxidation occurred by taking N2 as a unit. Absorption spectra of linear oligoarylamines at various oxidative states were obtained to investigate their charge transfer behaviors. Moreover, DFT-computed isotropic hyperfine coupling constants and spin density were in accordance with the EPR experiment, and gave a close examination of oligoarylamines at charged states.

Electrochemically controlled multiple hydrogen bonding between triarylamines and imidazoles.

By increasing the number of amino substituents on triarylamine, the extent of hydrogen bonding between the oxidized form of triarylamine and imidazole could be electrochemically controlled. Three behaviors, depending on the interaction between oxidized amine and imidazole, were obtained in CV patterns. DFT calculation was used to confirm that the electron density of protons of the amino group decreased as the amino moiety increased.

Studies on the structure of N-phenyl-substituted hexaaza[1(6)]paracyclophane: synthesis, electrochemical properties, and theoretical calculation.

The N-phenyl-substituted hexaaza[1(6)]paracyclophane (3, hexamer) has been synthesized successfully in two steps and the noncoplanar conformation was calculated by gaussian program. The electrochemical properties exhibited lots of interesting results and each overlapping oxidative wave contained two-electron transfer.

Selective ring expansion alkylation of formyl[2.2.1]bicyclic carbinols with C-nucleophiles: a unique route to cyclopentane derivatives.

Reactions of camphor-, and camphene-derived formyl [2.2.1]bicyclic carbinols with Grignard and organolithium reagents afford the corresponding regio- and stereospecific alkyl/aryl [3.2.1]bicyclic diols. Some of these bicyclic diols have been treated with lead tetraacetate to provide new chiral cyclopentane derivatives. A plausible mechanism of the ring expansion-alkylation reaction is proposed.

Isolation and quantitative analysis of cryptotanshinone, an active quinoid diterpene formed in callus of Salvia miltiorrhiza BUNGE.

Effect of N(6)-benzyladenine (BA) on tanshinone formation in callus cultures of Salvia miltiorrhiza was examined in an attempt to increase the productivity of the medicinal compound, cryptotanshinone. Primary callus was induced by culturing leaf explants on Murashige and Skoog's (MS) basal medium supplemented with 1.0 mg l(-1) of 2,4-dichlorophenoxyacetic acid (2,4-D) in darkness. The callus proliferated further on MS basal medium containing 1.0 mg l(-1) 2,4-D and 0.5 mg l(-1) BA and was analyzed for cryptotanshinone by high performance liquid chromatography (HPLC). The HPLC results indicated that it contained small amounts of cryptotanshinone (0.26+/-0.05 mg/g dry wt). Omission of 2,4-D from the medium resulted in a marked increase in the content of cryptotanshinone in callus. The HPLC analysis revealed that the content of cryptotanshinone in the callus cultured on the MS basal medium supplemented with 0.1, 0.2, 0.5, 1.0, and 2.0 mg l(-1) of BA was significantly higher than the marketed crude drug (processed underground parts of S. miltiorrhiza). Maximum yield of cryptotanshinone (4.59+/-0.09 mg/g dry wt) was observed in the callus cultured on MS basal medium supplemented with 0.2 mg l(-1) BA for 60 d. Cryptotanshinone was isolated from callus through silica gel column chromatography followed by preparative TLC and characterized based on NMR and mass spectral data.