Nine constituents including six xanthone-related compounds isolated from two ascomycetes, Gelasinospora santi-florii and Emericella quadrilineata, found in a screening study focused on immunomodulatory activity

Five metabolites tentatively called GS-1 (1)-5 (5) from Gelasinospora santi-florii, and four tentatively called EQ-4 (6), EQ-6 (7)-8 (9) together with 1-4 from Emericella quadrilineata have been isolated in a screening study on immunomodulatory fungal constituents. Among these nine metabolites, EQ-7 and 8 have been unknown. This time, the structures of GS-4 which has previously been isolated, EQ-7, and -8 have been determined to be (4R,4aS,9aR)-1,9a-dihydronidulalin A (4), (4S,4aR,9aR)-4a-carbomethoxy-1,4,4a,9a-tetrahydro-4,8-dihydroxy-6-methylxanthone (8), and 9-hydroxymicroperfuranone (9), respectively, and the six other metabolites have been identified. On bioassay, a dihydroxanthone, nidulalin A (1), a hexaketide, sordarial (5), and a xanthone, pinselin (7) have displayed significant immunosuppressive activities. The structure-activity relationships of these constituents have also been discussed.     

Conformational stabilities and structural parameters of (CH3)(n)CH(3-n) CFO molecules

Variable temperature (-60 to -100 degrees C) studies of the infrared spectra (3500-400 cm(-1)) of propionyl fluoride (CH3CH2CFO) and 2-methylpropionyl fluoride ((CH3)2CHCFO), dissolved in liquid xenon have been recorded. From these data, the enthalpy difference has been determined to be 329 +/- 33 cm(-1) (3.94 +/- 0.39 kJ/mol) for propionyl fluoride with the trans conformer (methyl group eclipsing the oxygen atom) more stable than the gauche form. For 2-methylpropionyl fluoride, the enthalpy difference has been determined to be 297 +/- 30 cm(-1) (3.55 +/- 0.36 kJ/mol) with the gauche conformer (methyl group eclipsing the oxygen atom) more stable than the trans form. From these DeltaH values along with assigned torsional fundamentals for both conformers and accompanying "hot bands" the potential functions governing the conformational interchange have been calculated. Utilizing the infrared data from the xenon solution and ab initio frequency predictions from MP2/6-31G* calculations, a few reassignments of the fundamentals have been made. Ab initio calculations have been carried out with several different basis sets up to MP2/6-311 + G** from which structural parameters and conformational stabilities have been determined. Additionally, force constants, infrared intensities, Raman activities, depolarization ratios, and scaled vibrational frequencies have been determined from MP2/6-31G* calculations. Adjusted structural parameters have been obtained from combined ab initio predicted values and previously reported microwave data. These parameters are compared to those obtained from either the earlier microwave and/or electron diffraction studies. Similar ab initio calculations and structural parameter determinations have been carried out for acetyl fluoride (CH3CFO) and trimethylacetyl fluoride ((CH3)3CCFO) and compared to the corresponding experimental results when appropriate.     

X-ray,vibrational spectra and density functional studies on cynacure

The solid-state X-ray diffraction, FT-IR and FT-Raman measurements of cynacure have been performed. Optimized molecular structures and normal vibrations of cynacure and 2-(methylthio)aniline have been calculated in the gas phase at the B3LYP/6-311++G** level. Scaling factors that bring computational gas-phase frequencies in closer agreement with the solid-state experimental data have been calculated for each vibration type. The observed IR and Raman bands of cynacure and 2-(methylthio)aniline have been assigned in the frameworks of the calculated mode frequencies as well as the calculated IR and Raman intensities. The assignments of the normal modes of cynacure have been compared with those of the benzene and 2-(methylthio)aniline modes. The effects of the substitution on the benzene vibrational frequencies have been investigated. 2-(Methylthio)aniline and cynacure both have four stable conformers. The calculated ground-state energetics and vibrational spectra of 2-(methylthio)aniline and cynacure suggest the coexistence of their stable conformers at the room temperature.     

Spectra and structure of silicon containing compounds. XXXIX. Raman and infrared spectra,conformational stability,vibrational assignment and ab initio calculations of n-propyltrifluorosilane

The infrared (3100-40 cm(-1)) spectra of gaseous and solid and Raman (3200-20 cm(-1)) spectra of liquid with qualitative depolarization values and solid n-propyltrifluorosilane, CH(3)CH(2)CH(2)SiF(3), have been recorded. Additionally the infrared spectra of the sample in nitrogen and argon matrices have been recorded. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 degrees C) studies of the infrared spectra of the sample dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 135+/-14 cm(-1) (1.62+/-0.17 kJ mol(-1)) with the anti conformer the more stable form. At ambient temperature it is estimated that there is 51+/-2% of the gauche conformer present. Also the enthalpy difference in the liquid was obtained from variable temperature studies of the Raman spectra and from three conformer pairs an average value of 179+/-18 cm(-1) (2.14+/-0.22 kJ mol(-1)) was obtained again with the anti form the more stable conformer. Relatively complete vibrational assignments are proposed for both conformers based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios which are supported by normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities, depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311+G(d, p) and 6-311+G(2d, 2p) basis sets. By utilizing the previously reported microwave rotational constants for five isotopomers of CH(3)SiF(3) along with ab initio predicted structural values, r(0) parameters have been obtained for methyltrifluorosilane. Similarly, from the ab initio predicted parameters "adjusted r(0)" parameters have been estimated for both conformers of n-propyltrifluorosilane. The results are discussed and compared with those obtained for some similar molecules.     

The visible absorption spectrum of OBrO, investigated by Fourier transform spectroscopy

By the utilization of a new laboratory method to synthesize OBrO employing an electric discharge, the visible absorption spectrum of gaseous OBrO has been investigated. Absorption spectra of OBrO have been recorded at 298 K, using a continuous-scan Fourier transform spectrometer at a spectral resolution of 0.8 cm(-1). A detailed vibrational and rotational analysis of the observed transitions has been carried out. The FTS measurements provide experimental evidence that the visible absorption spectrum of OBrO results from the electronic transition C(2A2)-X(2B1). Vibrational constants have been determined for the C(2A2) state (omega(1) = 648.3 +/- 1.9 cm(-1) and omega 2 = 212.8 +/- 1.2 cm(-1)) and for the X(2B1) state (omega 1 = 804.1 +/- 0.8 cm(-1) and omega 2 = 312.2 +/- 0.5 cm(-1)). The vibrational bands (1,0,0), (2,0,0), and (1,1,0) show rotational structure, whereas the other observed bands are unstructured because of strong predissociation. Rotational constants have been determined experimentally for the upper electronic state C(2A2). By modeling the band contours, predissociation lifetimes have been estimated. Further, an estimate for the absorption cross-section of OBrO has been made by assessing the bromine budget within the gas mixture, and atmospheric lifetimes of OBrO have been calculated using a photochemical model.     

Synthesis and study of some derivatives of cinchoninic acid

2-(4-Phenylquinolin-2-yl)cinchoninic and 2-(quinoxalin-2-yl)-5,6-benzocinchoninic acids have been synthesized. They have been subjected to decarboxylation and their chlorides and esters, amides, and anilides have been prepared. The spectral characteristics of the Cu(I) complexes of the derivatives synthesized have been obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1536–1537, November, 1973.     

Anthracene derivatives of benzo[f]quinoline. Synthesis,spectra, and luminescence

By condensation of 9-[N-(2-naphthyl)formimidoyl]anthracene with methyl ketones under conditions of acid catalysis, 1-R-3-(9-anthryl)benzo[f]quinolines have been obtained. The byproducts of the reaction have been identified: 1-R-3-(9-anthyl)-2-propen-1-ones and N-[1-(p-aminophenyl)-3-(9-anthryl)-2-propen-1-ylidene]-2-naphthylamines. The spectral and luminenscence properties of these compounds have been examined critically.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1536–1541, November, 1985.     

Ion exchange behaviour of hydrous tin oxide: Kinetics of anion exchange

The kinetic behaviour of Cl(-), Br(-) and SCN(-) exchanges on hydrous tin oxide have been investigated under conditions of particle diffusion and the limited bath technique. Values for the diffusion coefficients, energy of activation and entropy of activation have been calculated. The data obtained have been compared with those reported for other organic and inorganic exchangers.     

Enhancement of electroluminescence intensity in poly(3-alkylthiophene) with different alkyl side-chain length by doping of fluorescent dye

Electroluminescent diodes utilizing poly(3-alkylthiophene) (PAT) containing fluorescent dyes have been fabricated and their unique enhancement of emission characteristics have been studied. Remarkable enhancement of the electroluminescence efficiency has been observed for diodes with PAT doped with oxadiazole derivative (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole; PBD) and perylene derivative (N,N′ - Bis(2,5 - di - tert - butylphenyl) - 3,4,9,10 - perylenedi- carboximide; BPPC). The mechanism of emission enhancement by doping of PBD into PAT has been discussed with different alkyl side-chain lengths. © 1997 John Wiley & Sons, Ltd.     

Syntheses of 1,5-Benzothiazepines: Part XXXVI—Syntheses and Antimicrobial Evaluation of 2-(2-Chlorophenyl)-4-(4-chlorophenyl/2-thienyl)-2,5-dihydro-8-substituted-1,5-benzothiazepines

Six 5-substituted-2-aminobenzenethiols have been reacted with 3-(2-chlorophenyl)-1-(4-chlorophenyl)-2-propenone and 3-(2-chlorophenyl)-1-(2-thienyl)-2-propenone in dry ethanol saturated with dry HCl gas, to obtain twelve new compounds, 8-substituted-2-(2-chlorophenyl)-4-(4-chlorophenyl/2-thienyl)-2,5-dihydro-1,5-benzothiazepines in satisfactory yields. The structures of the final products have been assigned by elemental microanalyses data for elements, C, H, and N and by IR, ¹ H NMR, and mass spectroscopies. The synthesized compounds have been evaluated for their relative antimicrobial activity against the gram-positive bacteria, Staphylococcus aureus, gram-negative bacteria, Pseudomonas aeruginosa and the fungus, Candida albicans. The compounds have been found to show little antibacterial activity, but interestingly, showed significant antifungal activity.     

Synthesis of derivatives of 1-phenylhydropyrimidines

The synthesis has been effected, via the corresponding N-phenyl-ß-aminopropionic acids, of 1-(o-methoxyphenyl)-, 1-(o-ethoxyphenyl)-, and 1-(o-tolyl)dihydrouracils and also of 1-(o-methoxyphenyl)-, 1-(o-ethoxyphenyl)-, and 1-(o-tolyl)-2-thiodihydrouracils. The dihydrouracits and thiodihydrouracils obtained have been reduced with LiAlH₄ to the corresponding 2-oxohexahydro-, and 2-thioxohexahydropyrimidines. By the action of bromine and the subsequent splitting out of HBr, the dihydrouracils have been converted into 1-(o-methoxyphenyl)-, 1-(o-ethoxyphenyl)-, and 1-(o-tolyl)uracils.     

Spectra and structure of small ring compounds. LXVII vibrational spectra, variable temperature FT-IR spectra of krypton solutions, conformational stability and ab initio calculations of 1-bromosilacyclobutane

The infrared (3,200-30 cm(-1) spectra of gaseous and solid 1-bromosilacyclobutane, c-C3H6SiBrH, have been recorded. Additionally, the Raman spectra of the liquid (3,200- 30 cm(-1) with quantitative depolarization values and the solid have been recorded. Both the equatorial and the axial conformers have been identified in the fluid phases, Variable temperature ( - 105 to - 150 degrees C) studies of the infrared spectra of the sample dissolved in liquid krypton have been carried out. From these data the enthalpy difference has been determined to be 182 +/- 18 cm(-1) (2.18 +/- 0.22 kJ/mol) with the equatorial conformer the more stable rotamer and only conformer remaining in the annealing solid. At ambient temperature there is approximately 22% of the axial conformer present in the vapor phase. A complete vibrational assignment is proposed for both conformers based on infrared contours, relative intensities, depolarization values and group frequencies. The vibrational assignments are supported by normal coordinate calculations utilizing the force constants from ab initio MP2/6-31G(d) calculations. From the frequencies of the Si-H stretch, the Si-H bond distance of 1.483 A has been determined for both the equatorial and the axial conformers. Complete equilibrium geometries have been determined for both rotamers by ab initio calculations employing the 6-31G(d) and 6-311 +/- G(d,p) basis sets at levels of Hartree Fock (RHF) and/or Moller- Plesset with full electron correlation by the perturbation method to the second order (MP2). The results are discussed and compared to those obtained for some similar molecules.     

Vibrational spectra and structure of benzophenone and its (18)O and d10 labelled derivatives: an ab initio and experimental study

Infrared (4000-100 cm(-1)) and Raman (4000-10 cm(-1)) spectra of benzophenone, benzophenone-d10 and benzophenone-(18)O have been studied in the solid state and in solution and their fundamental frequencies have been assigned using isotopic frequency shifts and differential infrared linear dichroic spectra of oriented polycrystalline layers (4000-400 cm(-1)). Ab initio MO calculations have been carried out for the three benzophenone isotopomers at the HF/3-21G, 6-31G and 6-31G** levels and the computed vibrational frequencies have been compared with the experimental ones. Best agreement is achieved with the 6-31G data, the mean deviation being 25.4 cm(-1). The calculated isotopic frequency shifts induced by the (18)O and d10 labelling, are also in a good accordance with the measured ones. All geometry parameters calculated for the isolated molecule are in good agreement with the X-ray data for the benzophenone single crystal.     

Spectra and structure of silicon containing compounds. XXXII. Raman and infrared spectra,conformational stability,vibrational assignment and ab initio calculations of n-propylsilane-d0 and Si-d3

The infrared (3100-40 cm(-1)) and Raman (3100-20 cm(-1)) spectra of gaseous and solid n-propylsilane, CH(3)CH(2)CH(2)SiH(3) and the Si-d(3) isotopomer, CH(3)CH(2)CH(2)SiD(3), have been recorded. Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values obtained. Both the anti and gauche conformers have been identified in the fluid phases but only the anti conformer remains in the solid. Variable temperature (-105 to -150 degrees C) studies of the infrared spectra of n-propylsilane dissolved in liquid krypton have been recorded and the enthalpy difference has been determined to be 220+/-22 cm(-1) (2.63+/-0.26 kJ mol(-1)) with the anti conformer the more stable form. A similar value of 234+/-23 cm(-1) (2.80+/-0.28 kJ mol(-1)) was obtained for deltaH for the Si-d(3) isotopomer. At ambient temperature it is estimated that there is 30+/-2% of the gauche conformer present. The potential function governing the conformation interchange has been estimated from the far infrared spectral data, the enthalpy difference, and the dihedral angle of the gauche conformer, which is compared to the one predicted from ab initio MP2/6-31G(d) calculations. The barriers to conformational interchange are: 942, 970 and 716 cm(-1) for the anti to gauche, gauche to gauche, and gauche to anti conformers, respectively. Relatively complete vibrational assignments are proposed for both the n-propylsilane-d(0) and Si-d(3) molecules based on the relative infrared and Raman spectral intensities, infrared band contours, depolarization ratios, and normal coordinate calculations. The geometrical parameters, harmonic force constants, vibrational frequencies, infrared intensities, Raman activities and depolarization ratios, and energy differences have been obtained for the anti and gauche conformers from ab initio MP2/6-31G(d) calculations. Structural parameters and energy differences have also been obtained utilizing the larger 6-311 + G(d,p) and 6-311 + G(2d,2p) basis sets. From the isolated Si-H stretching frequency from the Si-d(2) isotopomer the r(0) distances of 1.484 and 1.485 A have been determined for the SiH(s) and SiH(a) bonds, respectively, for the anti conformer, and 1.486 A for the SiH bond for the gauche conformer. Utilizing previously reported microwave rotational constants for the anti conformer and the determined SiH distances along with ab initio predicted parameters 'adjusted r(0)' parameters have been obtained for the anti conformer. The results are discussed and compared to those obtained for some similar molecules.     

Synthesis,characterization, crystal structure and DFT studies on 3-(1H-benzo[d][1,2,3]triazol-1-yl)-1-(4-ethylphenyl)-1-oxopropan-2-yl-4-ethylbenzoate

3-(1H-benzo[d][1,2,3]triazol-1-yl)-1-(4-ethylphenyl)-1-oxopropan-2-yl-4-ethyl-benzoate (BEOE) has been synthesized and characterized by elemental analysis, IR, UV–vis and fluorescence spectroscopy. Its crystal structure has also been determined by X-ray single crystal diffraction. For the title compound, density functional theory (DFT) calculations of the structure and vibrational frequencies have been performed at B3LYP/6-31G* level of theory. Based on the vibration analysis, thermodynamic properties of the title compound have been calculated. The correlative equations between the thermodynamic properties and temperatures have also been listed. By using TD-DFT method, electron spectra of the title compound have been predicted, which suggests the B3LYP/6-31G* method can approximately simulate the electron spectra for the system presented here.     

Enzyme electrode probes obtained by electropolymerization of monomers with PMS and selected dehydrogenase enzymes

5-methylphenazonium methylsulphate, (commonly named phenazine methosulphate, PMS) mediated electroxidation of beta-nicotinamide adenine dinucleotide (phosphate), reduced form, (NAD(P)h), on platinum, gold and carbon electrodes has been studied by electropolymerization of 1,2-, 1,3-, 1,4-diaminobenzene (DAB), pyrrole-2-carboxylic acid (PY-2-COOH) and 4,4'-dihydroxybenzophenone (DHB) in presence of PMS using cyclic voltammetry. The electroxidation of ascorbic acid has been evaluated on the electrodes electropolymerized in absence and in presence of PMS. The same experiments have been carried out with NAD(P)H in solution. Results showed that the NAD(P)H is oxidised by PMS coimmobilized with the polymer film on the electrode surface. NAD(P)H has been measured in the range 10(-6)-10(-2)mol l(-1) with a detection limit of 5 x 10(-7) mol 1(-1). Amperometric measurements of NAD(P)H have been carried out at -0.10 V and the efficiency of different elecrodes based on different materials has been studied. The electropolymerization has been also carried out in presence of PMS and selected dehydrogenase enzymes. The activity of these enzymes has been tested amperometrically at -0.1 V. Enzyme substrates such as glucose, lactate and glutamate have been measured in the range 5 x 10(-6)-1 x 10(-2) mol 1(-1) with a detection limit 1 x 10(-6) mol 1(-1). Also the stability of these probes during time has been evaluated.     

New features on the fragmentation and differentiation of C-glycosidic flavone isomers by positive electrospray ionization and triple quadrupole mass spectrometry

Six flavone mono-C-glucosides, four standards (beta-D-glucopyranosyl-(1 --> C-6)- and -(1 --> C-8)- apigenin and luteolin) and two others from lemon juice (beta-D-glucopyranosyl-(1 --> C-6)- and -(1 --> C-8)-diosmetin) have been studied in order to analyze their fragmentation patterns. Initial separation was carried out using high-performance liquid chromatography with diode-array detection (HPLC/DAD) coupled to an electrospray ionization (ESI) interface and a triple quadrupole mass spectrometer. Several systematic differences between collision-induced dissociation tandem mass (CID-MS/MS) spectra of C-6- and C-8-isomers have been found and some general guidelines and two new diagnostic product ions have been proposed for the differentiation of C-6- and C-8-flavonoid glycosides. These results have been successfully applied to the characterization of two flavone C-glycosides found in lemon juice, and mass spectra of a flavone di-C-glycoside detected in lemon juice have been studied and interpreted.     

Novel Fluorine Containing Tetrathiafulvalenes for the Preparation of Langmuir-Blodgett Films

The novel fluorinated tetrathiafulvalenes: tetra(2,3,5,6-tetrafluorobenzylthio)-, dimethyldi(2,3,4,5,6-pentafluorobenzylthio)-, dimethyldi(2,3,5,6-tetrafluorobenzylthio)-, dimethyldi[3,5-di(trifluoromethyl)benzylthio]-, and dimethyldi(2-fluoro-4-bromobenzylthio)tetrathiafulvalenes have been synthesized in order to prepare Langmuir-Blodgett films. Their cyclic voltamograms have been studied and these show two, reversible, one-electron oxidation waves. A novel series of fluorinated benzylthio- and benzoylthio-1,3-dithiole-2-thiones and -2-ones has been synthesized.     

Alkaloids ofNitraria schoberi. Structure of nitraraine

The dehydration of nitraraine leads to the formation of 1-(2′,6′-dimethylbenzyl)-β-carboline, together with other products. Several isomeric 1-(dimethylbenzyl)-β-carbolines have been synthesized for comparison. The products of acylation, hydrogenation, and oxidation of the alkaloid nitraraine have been studied. The results obtained have shown its structure as (±)-16-hydroxymethylyohimb-16-ene.     

5-Substituted pyrimidine derivatives

The properties and reactivities of 4-hydroxy- and 2,4-dihydroxy-5-(β-hydroxyethyl)pyrimidines and of the products of their transformations have been studied. 4-Chloro- and 2,4-dichloro-5-(β-chloroethyl)pyrimidines have been obtained. A number of 4-alkyl(aryl)amino-5-(β-chloroethyl)pyrimidines have been synthesized, and they have been converted into derivatives of 5,6-dihydropyrrolo[2,3-d]pyrimidine.