Preparation,crystal structure,and spectroscopic,chemical, and electrochemical properties of (2E,4E)-1,4-di(3-guaiazulenyl)-1,3-butadiene compared with those of (E)-1,2-di(3-guaiazulenyl)ethylene

Wittig reaction of (E)-3-(3-guaiazulenyl)propenal (11) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (9) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title new (2E,4E)-1,3-butadiene derivative 4, in 33% isolated yield, which upon treatment with hexafluorophosphoric acid (i.e., 65% HPF₆ aqueous solution) in tetrahydrofuran (=THF) at 25 °C for 1 h under aerobic conditions affords a new air (two-electron) oxidation product (E)-ethylene-1,2-bis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (14), quantitatively, and further, zinc-reduction of 14 in trifluoroacetic acid (=CF₃COOH) at 0 °C for 1 h under argon reverts 4, quantitatively. Along with the above interesting results, our discovered another preparation method, spectroscopic properties, crystal structure, and electrochemical behavior of 4, which serves as a strong two-electron donor and acceptor, compared with those of the previously reported (E)-1,2-di(3-guaiazulenyl)ethylene (3) are documented in detail.     

Preparation and characterization of the inclusion complexes of equol with sulfobutylether-β-cyclodextrin: their antioxidant activity and dissolution evaluation

The formation of inclusion complexes between S-(?)-equol (SEq) and cyclodextrins (CDs) was investigated. The binding constant (K_c) of the SEq/sulfobutylether-β-cyclodextrin (SBE-β-CD) inclusion complex was determined to be 1600 L/mol based on UV data. The phenyl ring of the SEq molecule was found to be inserted from the secondary hydroxyl face of the SBE-β-CD as evidenced from ¹H–¹H rotating frame nuclear Overhauser effect spectroscopy (ROESY) NMR. The thermal properties of the solid SEq/SBE-β-CD inclusion complexes prepared by physical mixing, kneading and freeze-drying methods were studied by differential scanning calorimetry. For the solid complex obtained by the freeze-drying method, the endothermic peak corresponding to the melting point of SEq disappeared. The solid SEq/SBE-β-CD complexes exhibited a high score in antioxidant activity evaluation tests compared to SEq alone. Dissolution test revealed that the solid complex obtained by freeze-drying method had improved dissolution of SEq.     

Separation of rhenium by extraction with crown ethers and flow-injection extraction—spectrophotometric determination with Brilliant Green

The extraction behavior of perrhenate with crown ethers was studied and methods for the separation and determination of rhenium were developed. The distribution ratio of perrhenate with dicyclohexano-18-crown-6 (DC18C6) increases with increases in the dielectric constant of organic solvents and in the potassium ion concentration of aqueous solution. The molar ratios of crown ether to KReO₄ in the extracted species are probably 1:1 for DC18C6, dibenzo-18-crown-6 and 18-crown-6 and 2:1 for benzo-15-crown-5 and 15-crown-5. Microgram amounts of rhenium were satisfactorily separated from large amounts of molbdenum(VI) by extraction with DC18C6 in 1,2-dichloroethane from 2 M potassium hydroxide solution containing tartrate and by back-extraction with sodium phosphate buffer solution after the addition of a twofold volume of hexane to the organic phase. Rhenium was determined by the flow-injection extraction-photometric method with Brilliant Green. Rhenium was satisfactory determined in molybdenite and other ore samples.     

SOLID-STATE PHOTOCHEMISTRY OF INDOLES WITH NAPTHALENE AND PHENANTHRENE

Abstract— Solid-state irradiation of mixed crystals prepared by meltinga 1:3 molar mixture of indole and phenanthrene followed by resolidifying the melt gave an adduct 2a in 13.5% yield. An adduct 2b was obtained by irradiation of the mixed crystals of 3-methylindole and phenanthrene. Irradiation of the same mixtures of indoles and phenanthrene in solution gave no photoproduct. Irradiation of the mixed crystals of indole and naphthalene gave a similar photoadduct 3a, which was also formed in solution. The 1:1 mixed crystals of indole and phenanthrene and of indole and naphthalene were characterized by various spectroscopic methods. Among them powder X-ray diffraction spectral analysis and differential scanning calorimetry revealed that the former mixed crystal is a simple mixture of microcrystals of indole and phenanthrene, while the latter forms a molecular compound.     

Determination of midazolam and its metabolite as a probe for cytochrome P450 3A4 phenotype by liquid chromatography-mass spectrometry

This study demonstrated the analysis of midazolam and its metabolites by liquid chromatography-mass spectrometry (LC-MS) with a sonic spray ionization (SSI) interface. The analytical column was a YMC-Pak Pro C18 (50 mm x 2.0 mm i.d.) using 10 mM ammonium acetate (pH 4.8)-methanol (1:1) at a flow rate of 0.2 ml min(-1). The drift voltage was 100 V. The sampling aperture was heated at 110 degrees C and the shield temperature was 230 degrees C. The lower limits for the detection of midazolam and 1'-hydroxymidazolam were 26.3 and 112.76 pg injected, respectively. The calibration curves for midazolam and 1'-hydroxymidazolam were linear in the range of 0.1-5 microg ml(-1). Within-day relative standard deviations was less than 7%. The method was applied to the determination of midazolam in monkey plasma, and the analysis of midazolam and its metabolites in an in vitro study with recombinant cytochrome P450 (CYP) 3A4. This method is sufficiently sensitive and useful to elucidate the kinetics of midazolam metabolite formation. We also investigated the effect of propofol on the metabolism of midazolam using recombinant CYP3A4. Propofol competitively inhibited the metabolism of midazolam to 1'-hydroxymidazolam by CYP3A4.     

Synthesis of the new mannosidase inhibitors, diversity-oriented 5-substituted swainsonine analogues, via stereoselective Mannich reaction

5alpha-substituted swainsonine analogues were synthesized by Mannich reaction of an in situ generated (-)-swainsonine iminium ion intermediate. 5alpha-substituted swainsonine analogues were epimerized to their 5beta-isomers in protic solvent. [reaction: see text]     

Synthesis of Immunosuppressive Neoglycoproteins: Bovine Serum Albumin Coupled with 8-(Hydrazino-Carbonyl)Octyl 4- Or 6-O-α-D-Mannopyranosyl-α-D-Mannopyranoside

Abstract

Recombinant cytokines generated by bacteria, especially E. coli, are nonglycosylated. To investigate the effects of carbohydrates on their activities, we attempted to develop new cytokines by introduction of carbohydrates. As a model we synthesized neoglycoproteins in which potential immunoregulatory carbohydrates were coupled to bovine serum albumin(BSA). Mannose dimers with C9 spacer, Manα1-6Man, which is reported to be immunosuppressive, and a reference substance Manα1-4Man were synthesized as follows. Benzylidenation of 8-(methoxycarbonyl)octyl α-D-mannopyranoside (10), followed by acetylation and cleavage of the benzylidene acetal, gave a glycosyl acceptor (13) with a free hydroxyl group in the C-4 position. Glycosylation of 13 with acetobromomannose (8), followed by debenzylation, deacetylation, and hydrazidation, gave 8-(hydrazinocarbonyl)octyl 4-O-α-D-mannopyranosyl-α-D-mannopyranoside (1). Total yield of 1 from 10 was 25.1%. Tritylation of 10, followed by acetylation and detritylation, gave a glycosyl acceptor (18) with a free hydroxyl group in the C-6 position. Analogous condensation of 18 with 8, followed by deacetylation and hydrazidation, gave 8-(hydrazinocarbonyl)octyl 6-O-α-D-mannopyranosyl-α-D-mannopyranoside (2). Total yield of 2 from 10 was 22.9%. These mannose dimers were coupled to BSA by the acyl azide method. Using the antibodies against the mannose dimers, an enzyme linked immunosorbent assay (ELISA) was established to measure the small amount of mannose dimers coupled to proteins. These two neoglycoproteins appeared to inhibit the antigen-specific human T cell proliferation over 100 fold more efficiently than free mannose dimers.     

Inclusion complex of α-lipoic acid and modified cyclodextrins

The solubility of α-lipoic acid (LA) with the addition of modified cyclodextrins was investigated using the solubility method. The solubility of LA in the presence of β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), mono-6-O-glucopyranosyl-β-cyclodextrin (mono-G₁-β-CD), methyl-β-cyclodextrin (Me-β-CD), 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD), and sulfobutylether-β-cyclodextrin (SBE-β-CD) was higher than that of LA itself. In particular, the solubility of LA in the presence of SBE-β-CD was 20 times higher than that of LA alone. The structure of the inclusion complex of SBE-β-CD and LA in aqueous solution was examined by ¹H-¹H ROESY NMR spectroscopy. The 1,2-dithiolane moiety of LA was included from the secondary hydroxyl face of SBE-β-CD. The solid complexes of LA and SBE-β-CD were prepared by the kneading and freeze-drying methods. Formation of the solid complexes was confirmed by X-ray diffraction patterns (XRD), differential scanning calorimetry (DSC), and infrared spectroscopy (IR). The kneading and freeze-drying methods were successful for obtaining the solid inclusion complexes with improved thermal stability.     

Aqueous chromatography system using pH- and temperature-responsive stationary phase with ion-exchange groups

We report on the development of a novel analytical HPLC technique of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, ketoprofen and naproxen, with an isocratic aqueous mobile phase. In this study, we designed a new pH- and temperature-responsive copolymer of N-isopropylacrylamide (NIPAAm), butyl methacrylate (BMA) and N,N-dimethylaminopropylacrylamide (DMAPAAm). The copolymer was modified with cross-linked poly(NIPAAm-co-BMA-co-DMAPAAm) (IBD) hydrogel on to aminopropyl silica beads, and the products were evaluated as HPLC packing materials for an ion-exchange- and temperature-responsive chromatography. The property of the surface of the stationary phase was altered from hydrophilic to hydrophobic, and from charged to non-charged by changes in the temperature and pH. In addition, it is possible that ion-exchange groups can appear or be hidden on the polymer chain surface by temperature changes. The interactions of NSAIDs with this stationary phase were controlled by the temperature and the pH with a constant aqueous mobile phase. PH- and temperature-responsive chromatography is expected to be useful for the separation of pharmaceuticals and biomolecules.     

Aqueous chromatography system using temperature-responsive polymer-modified stationary phases

Extensive research has been carried out on functional polymers which are currently playing important roles in various fields such as medicine and engineering. Such functional polymers which respond to various kinds of stimuli are termed 'intelligent materials'. Poly(N-isopropylacrylamide) (PNIPAAm), a temperature-responsive polymer, was utilized as a chromatography column matrix modifier for a novel chromatographic approach in which only aqueous media are used as a mobile phase. The ability of the developed temperature-responsive chromatography system to separate solutes without using an organic solvent is advantageous from the point of view of maintaining the structure and activity of bioactive compounds. Recently, we designed and synthesized a new pH- and temperature-responsive copolymer as a representative of such environment-responsive polymers and grafted it onto aminopropyl silica beads. The products were evaluated as HPLC packing materials for separation systems based on a new concept, according to which the properties of the stationary phase surface are altered by external stimuli such as pH and temperature. This chromatography system utilizing the PNIPAAm copolymer is very useful for the separation of bioactive substances, such as proteins and peptides, because separation in the aqueous mobile phase is controlled solely by changing the temperature. This analytical system reduces organic waste because no organic solvent is used to separate the solutes and can therefore be classified as environmentally friendly. Future medical and pharmaceutical applications are expected.