Protective Effect of Ferulic Acid against Hydrogen Peroxide Induced Apoptosis in PC12 Cells

Ferulic Acid (FA) is a highly abundant phenolic phytochemical which is present in plant tissues. FA has biological effects on physiological and pathological processes due to its anti-apoptotic and anti-oxidative properties, however, the detailed mechanism(s) of function is poorly understood. We have identified FA as a molecule that inhibits apoptosis induced by hydrogen peroxide (H₂O₂) or actinomycin D (ActD) in rat pheochromocytoma, PC12 cell. We also found that FA reduces H₂O₂-induced reactive oxygen species (ROS) production in PC12 cell, thereby acting as an anti-oxidant. Then, we analyzed FA-mediated signaling responses in rat pheochromocytoma, PC12 cells using antibody arrays for phosphokinase and apoptosis related proteins. This FA signaling pathway in PC12 cells includes inactivation of pro-apoptotic proteins, SMAC/Diablo and Bad. In addition, FA attenuates the cell injury by H₂O₂ through the inhibition of phosphorylation of the extracellular signal-regulated kinase (ERK). Importantly, we find that FA restores expression levels of brain-derived neurotrophic factor (BDNF), a key neuroprotective effector, in H₂O₂-treated PC12 cells. As a possible mechanism, FA increases BDNF by regulating microRNA-10b expression following H₂O₂ stimulation. Taken together, FA has broad biological effects as a neuroprotective modulator to regulate the expression of phosphokinases, apoptosis-related proteins and microRNAs against oxidative stress in PC12 cells.     

Unique inclusion properties of crystalline powder p-tert-butylthiacalix[4]arene toward alcohols and carboxylic acids

Powdery crystals of p-tert-butylthiacalix[4]arene (2) selectively include EtOH from 1:1 mixtures of MeOH-EtOH and EtOH-PrOH, and EtCO(2)H from HCO(2)H-EtCO(2)H. On the other hand, no acid is included from HCO(2)H-MeCO(2)H, even though MeCO(2)H is included from the neat acid. The origins of these phenomena are discussed based on X-ray analysis of inclusion crystals prepared separately by crystallization.     

Synthesis of mono- and 1,3-diaminocalix[4]arenes via Ullmann-type amination and amidation of 1,3-bistriflate esters of calix[4]arenes

Practical methods are described for the preparation of monoamines 4 and 1,3-diamines 5, bearing one or two amino group(s) instead of the hydroxy group(s) at the 28-position or at both the 26- and 28-positions of p-tert-butylcalix[4]arene (1a) and p-tert-butylthiacalix[4]arene (1b), via the Ullmann-type amination or amidation. Thus, the copper-catalyzed or mediated amination of the 1,3-bistriflate ester (2a) of 1a with benzylamine affords either mono(benzylamino) triflate 7a or 1,3-bis(benzylamine) 8 in a high yield, depending on the reaction conditions. On the other hand, the 1,3-bistriflate ester (2b) of 1b resists disubstitution and produces, under stoichiometric conditions, mono(benzylamino) triflate 7b. The disubstitution of 2b is achieved by amidation with tosylamide, giving 1,3-bis(tosylamide) 17b. The hydrogenolysis of the benzylamino moiety of 7a, followed by the hydrolysis of the Tf moiety, affords monoamine 4a, while the hydrogenolysis of 8 affords 1,3-diamine 5a. The amino moiety of 7b can be deprotected under acidic conditions to give, after hydrolysis, monoamine 4b. The hydrolysis of 17b affords 1,3-diamine 5b. The overall yields of compounds 4a, 4b, 5a, and 5b are 72%, 45%, 78%, and 24%, respectively, based on commercially available compounds 1 and are much higher than the ones previously reported in the literature.     

Highly Selective Copper‐Catalyzed Hydroboration of Allenes and 1,3‐Dienes

The highly selective copper‐catalyzed hydroboration of allenes has been developed. Allylboranes and alkenylboranes were selectively prepared by the judicious choice of catalytic species (copper hydride and boryl copper). Furthermore, two types of alkenylboranes could be selectively synthesized by the choice of an appropriate ligand. Mechanistic studies confirmed that the protonation of a (Z)‐σ‐allyl copper species, which was isolated and structurally characterized by single‐crystal X‐ray diffraction, was a key step in these reactions. Besides allenes, this method is also applicable to the selective hydroboration of 1,3‐diene derivatives to afford allylboranes and homoallylboranes.     

Highly chemoselective hydrogenation with retention of the epoxide function using a heterogeneous Pd/C-ethylenediamine catalyst and THF

In general, palladium-carbon (Pd/C) catalyzed hydrogenation of epoxides affords the corresponding primary and secondary alcohols as a mixture. It has been found that the catalytic activity of a Pd/C -ethylenediamine complex catalyst [Pd/C(en)] in the hydrogenolysis of epoxide functions is drastically reduced. Herein we describe a mild and chemoselective method for the hydrogenation of olefin, nitro, and azide functions with retention of the epoxide function. The chemoselectivity was accomplished by using a combination of 5% Pd/C(en) and THF as solvent. A significant drop in the chemoselectivity of the hydrogenation is observed with 5% Pd/C(en) in MeOH. These results reinforce the utility of epoxides as important precursors of alcohols in synthetic chemistry.     

Crystal Structure and Property of Perovskite-Type Oxides Containing Ion Vacancy

Studies on the role of oxygen vacancy in structural change of nonstoichiometric perovskites and a property of oxygen-deficient perovskite-related K₂NiF₄ compounds are reviewed.The structural changes on which the authors focused are cation ordering and lattice distortion. The relationship between the distortion and oxygen vacancy was investigated by comparing the structures of Sr₂(Sr_1-xM_x)TaO_6-d (M = Ca²⁺ and Nd³⁺) solid solutions. It was found that distortion of a perovskite-type lattice decreased with an increasing amount of oxygen vacancies. In order to investigate the relationship between the cation ordering on octahedral sites and oxygen vacancy, structures of stoichiometric Sr_2-xLa_xCo_1-yTa_1+yO₆ and oxygen-deficient Sr_2-xLa_xMg_1-yTa_1+yO_6-d solid solutions were compared. The authors' work reveals that the cation ordering affects the amount of oxygen vacancies in addition to cation charge and size.