Studies on topical antiinflammatory agents. III. Synthesis of 17 alpha-acyloxy-9 alpha-fluoro-11 beta-hydroxy-16 beta-methyl-1,4-pregnadiene-3,20-dione 21-thio derivatives and related compounds

A series of 21-thio derivatives of 9 alpha-fluoro-11 beta,17 alpha-dihydroxy-16 beta-methyl-1,4-pregnadiene-3, 20-dione 17-esters and related compounds were synthesized and evaluated as topical antiinflammatory agents. These compounds were prepared by the reaction of 9 alpha-fluoro-11 beta,17 alpha,21-trihydroxy-16 beta-methyl-1,4-pregnadiene-3, 20-dione (betamethasone, I) 17-ester derivatives and various mercapto compounds. A structure-activity relationship study revealed that the structural combination of a thio group at the 21-position and an ester group at the 17-position contributed to vasoconstrictive activity. Among these compounds, the 21-methylthio 17-propanoate compound (6) was found to have the most potent activity, being more potent than betamethasone 17-valerate (BV).     

Quenching of a photosensitized dye through single-electron transfer from trivalent phosphorus compounds

Various types of trivalent phosphorus compounds 1 undergo single-electron transfer (SET) to the photoexcited state of rhodamine 6G (Rho+*) in aqueous acetonitrile to quench the fluorescence from Rho+*. The rate constants kp for the overall SET process were determined by the Stern-Volmer method. The rate is nearly constant at a diffusion-controlled limit in the region of E1/2(1) < 1.3 V (vs Ag/Ag+), whereas log kp depends linearly on E1/2(1) in the region of E1/2(1) > 1.3 V, the slope of the correlation line being -alphaF/RT with alpha = 0.2. The potential at which the change in dependence of log kp on E1/2(1) occurs (1.3 V) is in accordance with the value of E1/2(Rho+*) (1.22 V) that has been obtained experimentally. Thus, the SET step is exothermic when E1/2(1) < 1.3 V and endothermic when E1/2(1) > 1.3 V. The alpha-value (0.2) obtained in the endothermic region shows that the SET step from 1 to Rho+* is irreversible in this region. Trivalent phosphorus radical cation 1*+ generated in the SET step undergoes an ionic reaction with water in the solvent rapidly enough to make the SET step irreversible. In contrast, the SET from amines 2 and alkoxybenzenes 3 to Rho+* is reversible when the SET step is endothermic, meaning that the radical cations 2*+ and 3*+ generated in the SET step undergo rapid "back SET" in the ground state to regenerate 2 and 3.     

Stereochemical control in yeast reduction

A substrate which is subjected to yeast reduction has been modified by iodination or phenylsulfonylation. Both substituents improves chemical and optical yields and control the stereochemical course of the reduction.     

Magnesium, parathyroid hormone and osteocalcin in the sera of hospitalized patients with chronic alcoholism

Levels of parathyroid hormone (PTH) and osteocalcin in hypomagnesemic sera of chronic alcoholism patients were carried out to evaluate the roles of chronic alcohol poisoning on bone metabolism. Serum gamma-GTP activity showed inverse relationships among serum Mg and osteocalcin in these patients and PTH levels were also more decreased in these patients than in healthy subjects. These results indicated that the direct actions of alcohol might be brought about by the deterioration of bone metabolism, due to the decrease of serum PTH and osteocalcin levels by chronic alcohol poisoning.     

Correlation between acoustic cavitation noise and yield enhancement of sonochemical reaction by particle addition

The mechanism of the effect of particle addition on sonochemical reaction is studied through the measurements of frequency spectrum of sound intensity for evaluating the cavitation noise and the absorbance for the liberation of iodine from an aqueous solution of KI as an index of oxidation reaction by ultrasonic irradiation in the presence or absence of alumina particles. As it is expected that both the acoustic noise and a rise in temperature in the liquid irradiated by intense ultrasound will increase with the number of collapsing bubbles, these are supposed to be the best tools for evaluating the relative number of bubbles. In the present investigation, it has been shown that the addition of particles with appropriate amount and size results in an increase in the absorbance when both the acoustic noise and the rise in the liquid temperature due to cavitation bubbles also increase. This suggests that the enhancement in the yield of sonochemical reaction by appropriate particle addition comes from an increase in the number of cavitation bubbles. The existence of particle in liquid provides a nucleation site for cavitation bubble due to its surface roughness, leading to the decrease in the cavitation threshold responsible for the increase in the number of bubbles when the liquid is irradiated by ultrasound. Thus, from the present investigation, it is clarified that the particle addition has a potential to enhance the yield in the sonochemical reaction.     

The impact of surface Cu2+ of ZnO/(Cu1−xZnx)O heterostructured nanowires on the adsorption and chemical transformation of carbonyl compounds

The surface cation composition of nanoscale metal oxides critically determines the properties of various functional chemical processes including inhomogeneous catalysts and molecular sensors. Here we employ a gradual modulation of cation composition on a ZnO/(Cu_1−xZn_x)O heterostructured nanowire surface to study the effect of surface cation composition (Cu/Zn) on the adsorption and chemical transformation behaviors of volatile carbonyl compounds (nonanal: biomarker). Controlling cation diffusion at the ZnO(core)/CuO(shell) nanowire interface allows us to continuously manipulate the surface Cu/Zn ratio of ZnO/(Cu_1−xZn_x)O heterostructured nanowires, while keeping the nanowire morphology. We found that surface exposed copper significantly suppresses the adsorption of nonanal, which is not consistent with our initial expectation since the Lewis acidity of Cu²⁺ is strong enough and comparable to that of Zn²⁺. In addition, an increase of the Cu/Zn ratio on the nanowire surface suppresses the aldol condensation reaction of nonanal. Surface spectroscopic analysis and theoretical simulations reveal that the nonanal molecules adsorbed at surface Cu²⁺ sites are not activated, and a coordination-saturated in-plane square geometry of surface Cu²⁺ is responsible for the observed weak molecular adsorption behaviors. This inactive surface Cu²⁺ well explains the mechanism of suppressed surface aldol condensation reactions by preventing the neighboring of activated nonanal molecules. We apply this tailored cation composition surface for electrical molecular sensing of nonanal and successfully demonstrate the improvements of durability and recovery time as a consequence of controlled surface molecular behaviors.

Unexpected features of surface Cu²⁺ on ZnO/(Cu1−xZnx)O nanowires for molecular transformation and electrical sensing of carbonyl compounds were found.     

Robust synthesis of trifluoromethionine and its derivatives by reductive trifluoromethylation of amino acid disulfides by CF3I/Na/Liq.NH3 system

We disclose the reductive trifluoromethylation of chemically stable homocystine and cystine to provide corresponding trifluoromethyl ethers by the CF₃I/Na/Liq.NH₃ system. Both non-protected and protected homocystines can be nicely converted into trifluoromethylated methionines under the same condition. The method described offers a robust synthesis of pharmaceutically important trifluoromethionine, suitable for multigram synthesis. Pentafluoroethylation of homocystine was also achieved by the CF₃CF₂I/Na/Liq.NH₃ system.     

Correlation between Na* emission and "chemically active" acoustic cavitation bubbles.

The emission from electronically excited sodium atoms (Na*) from aqueous solutions containing NaCl or sodium dodecylsulfate under ultrasonic irradiation is studied. Evidence is presented that strongly suggests Na* emission arises from a population of bubbles that are sonochemically active but not producing sonoluminescence (SL). Results indicate that the Na* emission intensity is mainly dependent on the concentration of Na(+) ions near the bubble/solution interface. The results provide further insight into the origin of alkali metal spectral line emission from sonicated aqueous solutions containing sodium ions.     

Liquid-Liquid Extraction and Liquid Chromatographic Studies on Interactions of Inorganic Anions with Coordinatively Unsaturated Copper(II) Complexes of Heterocyclic Azo Compounds

The interactions between Cu(II) complexes with heterocyclic azo compounds and several anions were studied by equilibrium analysis of ion-pair extraction, RP-HPLC of metal complexes, and ion chromatography of anions on an ODS column coated with Cu(II) complexes of the long alkyl derivatives. Both ion-pair extraction and HPLC studies demonstrated that a dicationic complex with 8-(3,5-dibromo-2-pyridylazo)-5-aminoquinoline interacted with anions stronger than a monocationic complex with 2-(2-pyridylazo)methylphenol. Anions were more retained on the column coated with dicationic Cu(II) complex. Such differences were quantitatively ascribed to the first ion-pair formation of the dicationic complex giving a monocationic species.     

Finite element analysis of indentation on glass

The finite element method was applied to the analysis of the indentation process on glass. The calculated values of hardness for ideal elastic-plastic materials showed reasonable agreement with those obtained experimentally by other authors, but the calculated shapes of indentation were somewhat different from the real ones. When densification was taken into account, the calculated shapes of indentation showed better agreement with the real ones. The parameters for the calculation were estimated. The contribution of densification to the total deformation was estimated to be less than 45%, using the yield criterion as a basis for this estimation. A structure similar to the rosette-like structure was also calculated by this method. The finite element method was found to be one of the most effective methods for analysing indentations on glass, and it was shown that the mechanical properties of some glasses may be determined by precise observation of their indentations.