New chiral ether derivatives of 2-arylidene-p-menthane-3-ones as components of induced ferroelectric systems

New 2-arylidene-p-menthane-3-ones containing the ether bridging group in the arylidene fragment have been synthesized and studied as chiral dopants in ferroelectric liquid crystal mixtures. The ferroelectric properties of these compositions were compared with those for compositions including chiral dopants that do not contain any bridging group. The influence of bridging group and terminal alkyl substituent length in the dopant molecule on the ferroelectric parameters of systems studied is discussed. © 2001 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint, a member of the Taylor & Francis Group,.

Dichotomains A and B: Two new highly oxygenated phenolic derivatives from Dicranopteris dichotoma

Dichotomains A (1) and B (2), two new highly oxygenated phenolic derivatives that feature a spirodilactone moiety in their structures, were isolated from the fronds of Dicranopteris dichotoma. Their structures were elucidated on the basis of NMR and MS sp

Synthesis and anti-HIV-1 activities of novel podophyllotoxin derivatives

In order to explore the range of biological activities of the podophyllotoxin compound class, a novel series of derivatives of podophyllotoxin, which were conjugates containing stavudine and different structural podophyllotoxin analogues, were designed, s

Synthesis and anti-HIV-1 activity of S-dihydro(alkyloxy)benzyloxypyrimidine derivatives

Several 2-heteroaryl-, 2-heteroarylcarbonylmethyl-, 2-arylcarbonylmethyl, and 2-arylethyl derivatives of S-dihydro(alkyloxy)benzyloxypyrimidines have been synthesized and the anti-HIV activities of these compounds were tested in C8166 cell and against RT

Synthesis and Anti-Human Immunodeficiency Virus Type 1 Activity of (E)-N-Phenylstyryl-N-alkylacetamide Derivatives

A series of (E)-N-phenylstyryl-N-alkylacetamides, 5, were synthesized by direct reduction-acetylation of beta-arylnitroolefins, followed by N-alkylation. The title compounds were characterized by H-1-NMR, EIMS and IR analysis. All the synthesized compound

Synthesis of Zidovudine Derivatives with Anti-HIV-1 and Antibacterial Activities

Twelve novel zidovudine derivatives were prepared by modifying 5 '-hydroxyl group of sugar moiety (1-8) and 5-methyl group of thymidine nucleus (9-12) and characterized spectrally. The compounds were evaluated for anti-HIV-1, antitubercular and antibacter

Molecular docking and 3D-QSAR study of pyranmycin derivatives against 16S rRNA A site

To understand pharmacophore properties of pyranmycin derivatives and to design novel inhibitors of 16S rRNA A site, comparative molecular field analysis (CoMFA) approach was applied to analyze three-dimensional quantitative structure-activity relationship (3D-QSAR) of 17 compounds. AutoDock 3.0.5 program was employed to locate the orientations and conformations of the inhibitors interacting with 16S rRNA A site. The interaction mode was demonstrated in the aspects of inhibitor conformation, hydrogen bonding and electrostatic interaction. Similar binding conformations of these inhibitors and good correlations between the calculated binding free energies and experimental biological activities suggest that the binding conformations of these inhibitors derived from docking procedure were reasonable. Robust and predictive 3D-QSAR model was obtained by CoMFA with q(2) values of 0.723 and 0.993 for cross-validated and noncross-validated, respectively. The 3D-QSAR model built here will provide clear guidelines for novel inhibitors design based on the Pyranmycin derivatives against 16S rRNA A site. (c) 2005 Elsevier B.V. All rights reserved.

Relationship between the allelopathic activity and molecular structure of hydroxyl derivatives of benzoic acid and their effects on cyanobacterium Microcystis aeruginosa

The antialgal activities of benzoic acid, 2-hydroxybenzoic acid (salicylic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid (gallic acid) were studied on the growth of two strains of Microcystis aeruginosa (toxic FACHB 942 and non-toxic 469). The results showed that the sequence of 50% growth inhibition concentration (ErC50) of 6- compounds for both strains of M. aeruginosa followed the same order: gallic acid > 3,5-dihydroxybenzoic acid > 4-hydroxybenzoic acid > salicylic acid > 3-hydroxybenzoic acid > benzoic acid. The position and the numbers of hydroxy groups between the hydroxy group and carboxyl influenced the antialgal effects of phenolic acids. We also investigated the joint effects of benzoic acid, 4-hydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid on the growth of M. aeruginosa ( toxic FACHB 942). The mixture of phenolic allelochemicals showed the synergistic effects.

Evaluation of estrogenic activities and mechanism of action of perfluorinated chemicals determined by vitellogenin induction in primary cultured tilapia hepatocytes

Perfluorochemicals (PFCs) are emerging persistent organic pollutants (POPs) and are widely present in the environment, wildlife and humans. Recently, reports have suggested that PFCs may have endocrine-disrupting activities. In the present study, we have developed a non-competitive enzyme-linked immunosorbent assay (ELISA) method to investigate estrogenic activities of selected PFCs using vitellogenin (VTG) induction in primary cultured hepatocytes of freshwater male tilapia (Oreochromis niloticus). Cultured hepatocytes were exposed to various concentrations of perfluorooctanyl sulfonate (PFOS), pentadecafluorooctanoic acid (PFOA), 1H, 1H, 2H, 2H-nonafluoro-1-hexanol (4:2 FTOH), 1H, 1H, 2H, 2H-perfluorooctanol (6:2 FTOH) and 1H, 1H, 2H, 2H-perfluoro-1-decanol (8:2 FTOH) for 48h, while 17 beta-estradiol (E2) and 4-nonylphenol (4-NP) were used as positive controls. A dose-dependent induction of VTG was observed in E2-, 4-NP-, PFOS-, PFOA- and 6:2 FrOH-treated cells, whereas VTG levels remained unchanged in the 4:2 FTOH and 8:2 FTOH exposure groups at the concentrations tested. The estimated 48-h EC50 values for E2,4-NP, PFOS, PFOA and 6:2 FTOH were 4.7 x 10(-7), 7.1 x 10(-6), 1.5 x 10(-5), 2.9 x 10(-5) and 2.8 x 10(-5) M, respectively. In the time-course study, significant VTG induction took place at 24 h (E2), 6 It (4-NP), 48 It (PFOS), 48 It (PFOA), 72 It (4:2 FTOH), 12 h (6:2 FTOH), 72 h (8:2 FTOH), and increased further after 96 It of exposure. Co-exposure to binary mixtures of individual PFCs and E2 for 48 It significantly inhibited E2-induced hepatocellular VTG production in a dose-dependent manner except for 4:2 FTOH. The estimated 48-h IC50 (concentration of a compound that elicits 50% inhibition of maximally E2-induced VTG) values for PFOS, PFOA, 6:2 FTOH and 8:2 FTOH were 3.1 x 10(-7), 5.1 X 10(-7), 1.1 X 10(-6) and 7.5 x 10(-7) M, respectively. In order to further investigate the estrogenic mechanism of PFCs, the hepatocytes were co-exposed to binary mixtures of individual chemicals (E2,4-NP, PFOS, PFOA and 6:2 FTOH) and the known estrogen receptor inhibitor tamoxifen for 48 h; tamoxifen significantly inhibited the ability of these chemicals to stimulate vitellogenesis. The overall results demonstrated that PFOS, PFOA and FTOHs have estrogenic activities and that exposure to a combination of E2 and PFCs produced anti-estrogenic effects. The results of the estrogen receptor inhibition assay further suggested that the estrogenic effect of PFCs may be mediated by the estrogen receptor pathway in primary cultured tilapia hepatocytes. (c) 2007 Elsevier B.V. All rights reserved.