Mini-Reviews in Organic Chemistry - Volume 12, Issue 5, 2015

The paper represents a subsequent development of the Life Origination Hydrate Theory (LOH-Theory). It is shown that the natural amino-acids and primary proteins can originate together with DNAs in CH4-hydrate localizations from natural gas and niter; the thermodynamics and chemistry allow such reactions with no external energy sources.

A discussion of 1-hydroxypyranonaphthoquinones is presented that outlines the isolation and biological activity of the known naturally occurring members of this class of compounds. Synthetic approaches developed towards 1- hydroxypyranonaphthoquinones and analogues having potentially improved biological profiles are discussed with particular emphasis on the HRV 3C-protease inhibitor thysanone.

Recent developments in the field of biomimetic systems demand mechanical systems that are capable of delivering high power output per volume or mass. Volume changes within the conducting polymer layers are caused by the oxidation or reduction of the polymer. This volume change is the main source for actuators bending or deforming. Different actuator designs have been explored over the years to maximize bending, displacement or deformation. The bilayer design (two layers) incorporates a highly conductive metal layer along with the conducting polymer layer in its design. Trilayer designs (three layers) utilize an electrolyte storage layer to avoid delamination within the design. The storage layer allows for the trilayer design to operate freely in both liquid and air environments. To a limited extent zig zag conformations of polymers linked by small organic molecules or metal coordinating ligands have also been explored in the search for actuator materials with significant deformation and high current density. This review evaluates the contribution of polypyrrole and its derivatives in these actuator designs that impact on maximum displacement capability, current density and the lifetime of these actuator systems.

Our research group has published numerous papers over the last seven years on the reductive Heck reactions of unsaturated N-substituted tricyclic imides which have possible biological activities. The hydroarylation reactions of unsaturated N-substituted tricyclic imides using palladium(II) acetate as a catalyst were studied to obtain a series of new exo-aryl(hetaryl)-substituted tricyclic imides under stereoselective access.

As one of the most popular green solvents and catalysts, ionic liquids have been applied to various application fields including separation and purification, electrochemistry, chemical reaction, cellulose dissolution and so on. However, its further development has been restrained by the preparation and recycling methods due to its unique structure and physical-chemical property. Based on the status, current researches on the synthesis, purification and recycling of ionic liquids are reviewed, including many new techniques and tendencies. A series of synthesis methods are summarized and compared, and then the main influencing factors about the purity of ionic liquids as well as various ways of purification are discussed. The pretreatment of raw materials and the choice of synthetic procedure play key roles on the purification of ionic liquids. Finally, the recovery of ionic liquid is analyzed including distillation, membrane separation, two aqueous phase systems, extraction and so on. It is proposed that the choice of recycling method should be based on the different nature of ionic liquids.

The recent progress of Ramberg-Bäcklund reaction is reviewed both on the side of the reaction itself and its application in synthesis of functional organic molecules and natural products. In case of RB reaction itself, recent developments towards Meyer's modification and Hendrickson’s improvement are presented in detail, and then followed by new variants of Ramberg-Bäcklund rearrangements, including the epoxy-Ramberg-Bäcklund reaction, tandem Michael-addition-Ramberg- Bäcklund rearrangement, Diels-Alder-RB reaction. Recent synthetic application of RB reaction to prepare functional organic molecules as medium and large heterocyclic alkenes, optically pure polyoxygenated cycloalkene, chiral allylic and homoallylic compounds, are also discussed. Finally, applications of the Ramberg-Bäcklund process in synthesis of natural products are reviewed.

Heme oxygenase-1 (HO-1) production is induced in many cell types in response to numerous stimuli, such as the presence of hemes and other oxidants, endotoxin, pro-inflammatory cytokines, or heavy metals, as well as inflammation, hypoxia, or hyperoxia. In addition, HO-1 and the subsequent metabolites of heme catabolism appear to play vital roles in the regulation of important biological responses, including inflammation, oxidative stress, cell survival, and cell proliferation. Thus, HO-1 production is observed in a number of disease states, such as brain disorders, inflammatory diseases, diabetes mellitus, and cancer. Various signaling molecules have been identified as being involved in the regulation of HO-1 expression, including the mitogen-activated protein kinases (MAPKs), nuclear factor-ΚB (NF-ΚB), nuclear transcription factor erythroid-2 related factor 2 (Nrf2), AP-1 family, PI3K/Akt, and Bach1 signaling pathways. Moreover, recent studies have focused on the identification of HO-1-regulating natural products and the investigation of the mechanisms underlying their biological effects against various types of diseases. The biological effects of HO-1-regulating natural products appear to be related to their ability to modulate their antioxidant activity, anti-inflammatory effects, cell survival, and cell proliferation. In addition, these natural products, such as flavonoids, chalcone, lignin, xanthone, etc., have been shown to mediate their beneficial effects via HO-1 expression. These summarized reports strongly suggest that induction of HO-1 expression by natural products may be a promising therapeutic signaling target for the treatment of various human diseases.