Reversible formation of F+-centers over platinum promoted sulfated zirconia upon hydrogen treatment

Reversible formation of F⁺-centers was observed over platinum promoted sulfated zirconia in the presence and absence of hydrogen. The intensity of ESR signal of F⁺-centers was increased by treatment in He stream and it was decreased rapidly by supply of hydrogen in gas phase. This behavior seems to be related to proton spillover.     

Synthesis and inhibitory effect of novel glycyrrhetinic acid derivatives on IL-1 beta-induced prostaglandin E(2) production in normal human dermal fibroblasts

Olean-11,13(18)-dien-3beta,30-diol dihemiphthalate (3), which was derived from glycyrrhetinic acid (GA), has been reported to produce a potent of anti-inflammatory effect in in vivo assays. Using 3 as a lead compound, we attempted to synthesize some modified compounds which varied in the following; i) the position of a carboxyl group in the phthalate moiety, ii) the number of carboxyls attached to the benzoyl group, iii) conversion of benzene ring to another ring system, iv) the linkage form between the benzene ring and oleanene skeleton at position 3 and/or 30. These were screened for their inhibitory activity against interleukin-1 beta (IL-1 beta)-induced prostaglandin E(2) (PGE(2)) production in normal human dermal fibroblasts (NHDF). Although conversion of the ortho-carboxyl group of 3 into the meta-position or the para-position led to an increase in inhibitory activity, the elimination or increase of the carboxyl group resulted in loss of the inhibitory activity. Conversion of the ester bond to the amide bond at position 3 and/or 30 of 3 did not contribute to a significant increase in inhibitory activity. On the other hand, among the derivatives possessing an anthranilic acid moiety at position 30 of 3beta-O-acetyl-olean-11,13(18)-dien-30-oic acid (20), 3beta-hydroxy-30-nor-olean-11,13(18)-dien-20 beta-[N-(2-carboxyphenyl)]carboxamide (30) showed the most potent inhibitory activity (IC(50) 1.0 microM) in this series.     

Gamma-p-toluenesulfonyl-alpha,beta-epoxysilane: a new and practical acrolein beta-anion equivalent

[reaction: see text] Reaction of gamma-p-toluenesulfonyl-alpha,beta-epoxysilane with alkyl halides and aldehydes followed by treatment with n-Bu4NF affords alpha,beta-unsaturated aldehydes via a Brook rearrangement-mediated tandem process under extremely mild conditions.     

A convenient method for the preparation of α-vinylfurans by phosphine-initiated reactions of various substituted enynes bearing a carbonyl group with aldehydes

α-Vinylfurans were obtained by phosphine-initiated cyclization of various enynes bearing a carbonyl group at the ene end in the presence of various aldehydes, in moderate to high yields. The reaction may consist of 1,6-addition of phosphine to the enynes, ring closure, and Wittig reaction between the ylid resulting from cyclization and an aldehyde. Thus, various aldehydes were able to be used in the reaction. The reaction was influenced greatly by the substituents at the acetylene position (R¹) and the α-position of the carbonyl group (R³).     

Adsorption Isotherm of Water Vapor and Its Large Hysteresis on Highly Ordered Mesoporous Silica

The first and second adsorption–desorption isotherms of water vapor on a new mesoporous material derived from kanemite have been measured. The isotherms show unusual type V isotherms and large hysteresis. The type V isotherms, which have never been observed for the other adsorbates, suggest that the mesoporous material has a hydrophobic surface, although the hydrophobicity decreased after treatment with water vapor because of rehydration of the surface. The significantly large hysteresis could be explained by the difference in contact angle between adsorption and desorption.     

Michael addition reactions of acetoacetates and malonates with acrylates in water under strongly alkaline conditions

Michael addition reactions of acetoacetates and malonates with acrylates in a 5 M KOH aqueous solution without using any other catalysts are described. When they are either tert-butyl or benzyl esters, the reaction proceeded very rapidly to afford moderate to high yields of the corresponding bis-Michael adducts that are unexpectedly stable under these conditions.     

Stereoblock poly(lactic acid): synthesis via solid-state polycondensation of a stereocomplexed mixture of poly(L-lactic acid) and poly(D-lactic acid)

Stereoblock poly(lactic acid) consisting of D- and L-lactate stereosequences can be successfully synthesized by solid-state polycondensation of a 1:1 mixture of poly(L-lactic acid) and poly(D-lactic acid). In the first step, melt-polycondensation of L- and D-lactic acids is conducted to synthesize poly(L-lactic acid) and poly(D-lactic acid) with a medium-molecular-weight, respectively. In the next step, these poly(L-lactic acid) and poly(D-lactic acid) are melt-blended in 1:1 ratio to allow formation of their stereocomplex. In the last step, this melt-blend is subjected to solid-state polycondensation at temperature where the dehydrative condensation is allowed to promote chain extension in the amorphous phase with the stereocomplex crystals preserved. Finally, stereoblock poly(lactic acid) having high-molecular-weight is obtained. The stereoblock poly(lactic acid) synthesized by this way shows a higher melting temperature in consequence of the controlled block lengths and the resulting higher-molecular-weight. The product characterization as well as the optimization of the polymerization conditions is described. Changes in M(w) of stereoblock poly(lactic acid) (sb-PLA) as a function of the reaction time.     

Sensitive determination of anandamide in rat brain utilizing a coupled-column HPLC with fluorimetric detection

A fluorimetric determination method for N-arachidonoylethanolamine (anandamide) was developed using a precolumn fluorescence derivatization followed by coupled-column high-performance liquid chromatography (HPLC). Anandamide extracted from the rat brain tissue was derivatized with 4-N-chloroformylmethyl-N-methylamino-7-N, N-dimethylaminosulfonyl-2,1,3-benzoxadiazole (DBD-COCl), purified by a solid-phase extraction (Emporetrade mark), and assayed by the coupled-column HPLC. The HPLC consisted of phenyl (100 x 4.6 mm i.d. ) and octadecylsilica columns (250 x 4.6 mm i.d.), both connected by a six-port valve. The concentration of anandamide in rat brain was 3. 37 +/- 0.73 pmol/g with 6.47 and 3.57% of intra- and inter-day precisions, respectively. Using this method, we investigated the alteration of anandamide concentration in rat brain 30 min after administration of anandamide (2 mg/kg, i.p.) to rats pretreated with or without phenylmethylsulfonyl fluoride (PMSF; 30 mg/kg, i.p.), an inhibitor of amidohydrolase. In rats pretreated with PMSF, the brain concentration of anandamide was approx. 16-fold higher than that of rats without PMSF (p < 0.01).     

Determination of kynurenic acid levels in rat brain microdialysis samples and changes in kynurenic acid levels induced by N‐acetylaspartic acid

The levels of kynurenic acid, an endogenous antagonist of α₇ nicotinic acetylcholine and N‐methyl‐D ‐aspartate receptors, were measured in microdialysis samples obtained from the prefrontal cortices of rats using column‐switching high‐performance liquid chromatography with fluorescence detection. When the perfusate was constantly infused at a rate of 1.0 μ/min, the in vitro recovery of kynurenic acid through the dialysis membrane was approximately 20.4%, and the precision was within 1.31%. Endogenous kynurenic acid in the microdialysis sample was clearly detected using column‐switching high‐performance liquid chromatography. As an application study, N‐acetyl‐L ‐aspartic acid, an endogenous metabolite and precursor of N‐acetyl‐L ‐aspartyl‐L ‐glutamic acid, which is an agonist of metabotropic glutamate receptors, was infused for 120 min through the microdialysis probe. The kynurenic acid level significantly increased during the infusion of N‐acetyl‐L ‐aspartic acid, suggesting that kynurenic acid might have some association with N‐acetyl‐L ‐aspartic acid in vivo. Copyright © 2009 John Wiley & Sons, Ltd.