Photosensitized NADH formation system with multilayer TiO2 film

A TiO(2)/polymer film on a quartz plate fabricated by a layer-by-layer method was employed for NADH production from NAD(+) with lipoamide dehydrogenase and methyl viologen in Tris-HCl buffer on irradiation with UV light, and the ultra thin film prevented from enzyme deactivating effectively.     

Quantitative analysis of protein adsorption on a planar surface by Fourier transform infrared spectroscopy: lysozyme adsorbed on hydrophobic silicon-containing polymer

The adsorption of hen egg white lysozyme onto a solid polytris(trimethylsiloxy)silylstyrene (pTSS) surface from a D(2)O solution at pD 7 containing 100 mM NaCl and 10 mM sodium deuterated phosphate was monitored at 25 degrees C by Fourier transform infrared spectroscopy using the attenuated total reflection (ATR) method. The infrared spectrum attributed to only the adsorbed lysozyme was derived from the observed spectrum, and the amount of adsorbed lysozyme was determined as a function of time and lysozyme concentration. The kinetics of adsorption could be decomposed into two components, one of which was a process with a time constant of larger than 4 h(-1) and the other was a process with one of about 0.1 h(-1). These spectra showed that the lysozyme adsorbed in the faster process had a higher beta-structure content than the dissolved lysozyme. It was also found that the slower adsorption induced some conformational change in the lysozyme adsorbed in the faster process and/or that adsorbed in the slower process. After adsorption for 24 h, the pTSS surface was rinsed out with lysozyme-free solution. The resultant spectra of the surface indicated that the lysozyme adsorbed in the faster process was bound irreversibly on the surface and was changed to a conformer with a higher beta-structure content during the slower process. The experimental procedures and the theoretical applications for such a quantitative analysis in the ATR spectroscopic method are presented in detail.     

The synthesis of imidazo[4,5-c] - and v-triazolo[4,5-c] pyridazines

The parent imidazo[4,5-c]pyridazine (IV) has been prepared for the first time by three different routes. 1-Methylimidazo[4,5-c]pyridazine (XX) and 3-methylimidazo[4,5-c]pyridazine (XXVII) have been prepared by unequivocal syntheses. The constitution of the methylation product of imidazo[4,5-c]pyridazine-2-thiol (VIII) has been shown to be 2-methylthioimidazo[4,5-c]-pyridazine (IX) by the unequivocal syntheses of 1-methylimidazo[4,5-c]pyridazine-2-thiol (XXIII) and 3-methylimidazo[4,5-c]pyridazine-2-thiol (XXXIII). Likewise, the structure of the methylation product (XIII) was shown to be S-methylation by the unequivocal syntheses of 1-methyl-2-methylthio-6-chloroimidazo[4,5-c]pyridazine (XXIV) and 3-methyl-2-methylthio-6-chloroimidazo[4,5-c]pyridazine (XXXI), respectively. Several 7-substituted amino-v-triazolo-[4,5-c]pyridazines (XXXVIII) have been prepared from 7-chloro-v-triazolo[4,5-c]pyridazine (XXXVII).     

Reactions of acetonitrile coordinated to a nitrosylruthenium complex with H2O or CH(3)OH under mild conditions: structural characterization of imido-type complexes

The reaction of cis-[Ru(NO)(CH(3)CN)(bpy)(2)](3+) (bpy = 2,2'-bipyridine) in H(2)O at room temperature proceeded to afford two new nitrosylruthenium complexes. These complexes have been identified as nitrosylruthenium complexes containing the N-bound methylcarboxyimidato ligand, cis-[Ru(NO)(NH=C(O)CH(3))(bpy)(2)](2+), and methylcarboxyimido acid ligand, cis-[Ru(NO)(NH=C(OH)CH(3))(bpy)(2)](3+), formed by an electrophilic reaction at the nitrile carbon of the acetonitrile coordinated to the ruthenium ion. The X-ray structure analysis on a single crystal obtained from CH(3)CN-H(2)O solution of cis-[Ru(NO)(NH=C(O)CH(3))(bpy)(2)](PF(6))(3) has been performed: C(22)H(20.5)N(6)O(2)P(2.5)F(15)Ru, orthorhombic, Pccn, a = 15.966(1) A, b = 31.839(1) A, c = 11.707(1) A, V = 5950.8(4) A(3), and Z = 8. The structural results revealed that the single crystal consisted of 1:1 mixture of cis-[Ru(NO)(NH=C(O)CH(3))(bpy)(2)](2+) and cis-[Ru(NO)(NH=C(OH)CH(3))(bpy)(2)](3+) and the structural formula of this single crystal was thus [Ru(NO)(NH=C(OH(0.5))CH(3))(bpy)(2)](PF(6))(2.5). The reaction of cis-[Ru(NO)(CH(3)CN)(bpy)(2)](3+) in dry CH(3)OH-CH(3)CN at room temperature afforded a nitrosylruthenium complex containing the methyl methylcarboxyimidate ligand, cis-[Ru(NO)(NH=C(OCH(3))CH(3))(bpy)(2)](3+). The structure has been determined by X-ray structure analysis: C(25)H(29)N(8)O(18)Cl(3)Ru, monoclinic, P2(1)/c, a = 13.129(1) A, b = 17.053(1) A, c = 15.711(1) A, beta = 90.876(5) degrees, V = 3517.3(4) A(3), and Z = 4.     

Simultaneous determination of anthraquinones, their 8-beta-D-glucosides, and sennosides of Rhei Rhizoma by capillary electrophoresis

The simultaneous separation and determination of major anthraquinones (emodin, chrysophanol, rhein and their glucosides, aloe-emodin, sennoside A, and sennoside B) of Rhei Rhizoma were achieved by cyclodextrin modified capillary zone electrophoresis. The running electrolyte used in this method was 0.005 M alpha-cyclodextrin in 0.03 M borate buffer (pH 10.0) containing 20% acetonitrile, with an applied voltage of 20 kV.     

Investigation on the drying and decomposition of sodium oxalate

The drying of sodium oxalate at various temperatures was investigated by the micro-determination of the residual water in the heated sample and of the carbon monoxide produced by thermal decomposition. Sodium oxalate heated for 2hr above 200 degrees and cooled contains less than 20 ppm of water, and may be used as a standard for titrimetry. The decomposition of sodium oxalate into sodium carbonate and carbon monoxide was investigated by non-aqueous titrimetric micro-determination of carbon monoxide. The decomposition begins at 290 degrees and heating between 200 degrees and 250 degrees is recommended for the dehydration of sodium oxalate. The decomposition is complete between 750 degrees and 800 degrees within 20 min and the sodium carbonate obtained begins to decompose at above 810 degrees .     

The synthesis of pyrimido[4,5-c]pyridazines and pyrimido[5,4-c]pyridazines

The Hofmann reaction on 6-methylpyridazine-3,4-dicarboxamide (1) gave a mixture of 3-methylpyrimido[4,5-c]pyridazine-5,7-dione (2), 3-methylpyrimido[5,4-c]pyridazine-6,8-dione (3) and an acid (4) of unknown structure. The Hofmann reaction on pyridazine-3,4-dicarboxamide (9) gave a mixture of pyrimido[4,5-c]pyridazine-5,7-dione ( 10 ) and an acid ( 11 ) of unknown structure. The reaction of 3-amino-6-methylpyridazine-4-carboxamide ( 18 ) with ethyl orthoformate gave 3-methylpyrimido[4,5-c]pyridazin-5-one ( 21 ). 4-Aminopyridazine-3-carboxamide ( 36 ) upon fusion with urea gave pyrimido[5,4-c]pyridazine-6,8-dione ( 37 ) while with ethyl orthoformate 36 gave pyrimido[5,4-c]pyridazin-8-one ( 38 ). Pyrimido[5,4-c]-pyridazine-8-thione ( 39 ) was obtained by the action of phosphorus pentasulfide on 38. 4-Amino-3-cyanopyridazine ( 16 ) when treated with formamide produced 8-aminopyrimido[5,4-c]-pyridazine ( 41 ). The synthesis of 4-aminopyridazine-3-carboxamide ( 36 ) and 4-amino-3-cyanopyridazine ( 16 ), both key intermediates in the synthesis of the novel pyrimido[5,4-c]pyridazine ring system was accomplished by the Reissert reaction of 4-aminopyridazine-2-oxides and subsequent conversion of the nitrile to the amide.     

Thermal decomposition of ammonium uranates

The thermal decomposition of ammonium uranates precipitated from uranyl nitrate solution on the addition of aqueous ammonium hydroxide and hexamine under various conditions has been studied by means of thermogravimetry, differential thermal analysis, infrared spectroscopy and X-ray diffraction. Although all precipitates show the composition corresponding to UO₃ · NH₃ · H₂O, the precipitates with hexamine give X-ray diffraction patterns designed as types I and II, in which type I is similar to the precipitates with ammonia. As a result, it is concluded that ammonium uranates thermally decompose to amorphous UO₃ at about 400°, and transform to U₃O₈ via-UO₃ and/or-UO₃, latter being formed in the case of type II only.

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Zusammenfassung Die thermische Zersetzung von unter verschiedenen Bedingungen durch wässrige Lösungen von Ammoniumhydroxid und Hexamin aus Uranylnitrat-Lösung gefällten Ammoniumuranaten wurde mittels TG, DTA, IR-Spektroskopie und Röntgendiffraktometrie untersucht. Obwohl die Zusammensetzung aller Niederschläge der Formel UO₃ · NH₃ · H₂O entspricht, geben die mit Hexamin gefällten Niederschläge die als Typ I und II bezeichneten Röntgendiffraktogramme, von denen das des Typs I ähnlich dem der mit Ammoniak gefällten Niederschlage ist. Es wird festgestellt, daß Ammoniumuranate bei 400° thermisch zu amorphen UO₃ zersetzt werden und sich über-UO₃ und/oder-UO₃—wobei beim Typ II nur das letztere gebildet wird — in U₃O₈ umwandeln.

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, , - - , . @2 UO₃ · NH₃ · H₂O, , - I II. . , 400° UO₃ U₃O₈ -UO₃ -UO₃. II.

     

Interactions of cyclodextrins with dipalmitoyl, distearoyl, and dimyristoyl phosphatidyl choline liposomes. A study by leakage of carboxyfluorescein in inner aqueous phase of unilamellar liposomes

The interaction of cyclodextrins (CDs) with L-alpha-dipalmitoyl phopsatidyl choline (DPPC), L-alpha-distearoyl phosphatidyl choline (DSPC), and L-alpha-dimyristoyl phosphatidyl choline (DMPC) unilamellar liposomes was investigated by the leakage of carboxylfluorescein (CF) entrapped in the inner aqueous phase of liposomes, at 25 degrees C (DPPC and DSPC liposomes) and at 5 degrees C (DMPC liposomes). The efficiency of CDs for CF leakage was remarkable in the order of heptakis (2,6-di-O-methyl)-beta-CD (DOM-beta-CD) > alpha-CD > heptakis (2,3,6-tri-O-methy)-beta-CD (TOM-beta-CD) from DPPC liposomes, in the order of DOM-beta-CD > TOM-beta-CD > alpha-CD from DSPC liposomes and in the order of alpha-CD > DOM-beta-CD > TOM-beta-CD from DMPC liposomes. The other CDs used in the present studies, beta-CD, 2-hydroxylpropyl beta-CD, and gamma-CD scarcely induced the CF leakage from above the three liposomes. From the profiles of % CF leakage, together with measurements of differential scanning calorimetry, it was found that hydrophobic DOM-beta-CD penetrates the matrix of the liposomes to interact with them as well as TOM-beta-CD, and that less hydrophobic alpha-CD exists at the surface of the membrane to interact with the liposomes. Further, it was found that the interaction of CDs with liposomes changes depending not only on the length of fatty acid chain of phospholipid (condensation force and hydrophobicity) but also the hydrophobicity and the cavity size of CD.     

Syntheses of 4-(benzo[b]furan-2 or 3-yl)- and 4-(benzo[b]-thiophen-3-yl)piperidines with 5-HT2 antagonist activity

The syntheses of 4-(benzo[b]furan-3-yl)piperidines, 4-(benzo[b]furan-2-yl)piperidines and 4-(benzo[b]thiophen-3-yl)piperidines with 5-HT₂ antagonist activity are described. Reaction of 1-acetyl-4-(2,4-difluorobenzo-yl)piperidine 2 with methyl glycolate gave methyl 6-fluoro-3-(1-acetylpiperidin-4-yl)benzo[b]furan-2-carboxylate 3 , which was converted to 2-[2-[4-(benzo[b]furan-3-yi)piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo-[4,3-a]pyridin-3(2H)-one hydrochloride 9 . Analogous benzo[b]furans 17a-d and benzo[b]thiophenes 10a,b and 18a were prepared by a similar method. Cyclization of 4-fluoro-2-(4-pyridinylmethoxy)acetophenones 20a,b afforded 4-(benzo[b]furan-2-yl)pyridines 21a,b , which were converted to 2-[2-[4-(benzo[b]furan-2-yl)-piperidin-1-yl]ethyl-5,6,7,8-tetrahydro-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one hydrochlorides 24a,b. Among them, benzo[b]furans 9 and 17a,d and benzo[b]thiophenes 10 and 18a showed potent 5-HT₂ antagonist activity in vitro.