Water-soluble constituents of anise: new glucosides of anethole glycol and its related compounds

From the water-soluble portion of the methanolic extract of the fruit of anise (Pimpinella anisum L.), which has been used as a spice and medicine since antiquity, twelve new and five known glucosides of phenylpropanoids, including four stereoisomers of anethole glycol 2'-O-beta-D-glucopyranoside and four stereoisomers of 1'-(4-hydroxyphenyl)propane-1',2'-diol 2'-O-beta-D-glucopyranoside were isolated together with anethole glycols and guaiacyl glycerol. The structures of the new compounds were clarified by spectral investigation.     

First total synthesis of a novel monoterpenoid isoquinoline alkaloid, (+/-)-alangine

The structure including the stereochemistry of a novel monoterpenoid isoquinoline alkaloid, alangine, was confirmed by total synthesis via N-acyliminium cyclization to construct the isoquinoline skeleton and reductive cleavage of vinyl epoxide with Pd(0) catalyst.     

Preparation of Spherical Hydrous Silica Oxide Particles under Acidic Condition via Sol-Gel Processing

Preparation of spherical hydrous silica oxide particles via sol-gel processing was rarely reported. In this study, spherical silica particles were obtained in TEOS/AcOEt/AcOH 50% aq. system. The combination of AcOEt and AcOH 50% aq. widened the spherical particle-forming region. Their size ranged from some ten micrometers to some hundreds micrometers. Hydrophilic molecules or powders like Rhodamine 6G and phosphorescent powders were encapsulated in the spherical particles.     

Structures and chemical reactions of SO2 adsorbates studied by surface XAFS

Adsorption and surface chemical reactions of SO₂ on Ni, Cu and Pd metal surfaces are studied by using surface XAFS, as well as XPS and STM. It has turned out that SO₂ lies flat on the Ni(100), Ni(110) and Ni(111) surfaces, while it stands on Pd(100) and Pd(111). By raising the temperature, surface reactions occur on these metal surfaces. Typical reactions on Ni and Cu are 3SO₂ → S+2SO₃, while those on Pd are 2SO₂ → S+SO₄. The structures of the adsorbate species are elucidated.     

Kinetic and ESR studies on radical copolymerization of p-tert-butoxystyrene and di-n-butyl maleate in benzene

The copolymerization of p-tert-butoxystyrene (TBOSt) (M₁) and di-n-butyl maleate (DBM) (M₂) with dimethyl 2,2′-azobisisobutyrate (MAIB) in benzene at 60°C was studied kinetically and by means of ESR spectroscopy. The monomer reactivity ratios were determined to be r₁ = 2.3 and r₂ = 0 by a curve-fitting method. The copolymerization system was found to involve ESR-observable propagating polymer radicals under practical copolymerization conditions. The apparent rate constants of propagation (k_p) and termination (k_t) at different feed compositions were determined by ESR. From the relationship of k_p and f₁ (f₁ = [M₁]/([M₁] + [M₂])) based on a penultimate model, the rate constants of five propagations of copolymerization were evaluated as follows; k₁₁₁ = 140 L/mol s, k₂₁₁ = 3.5 L/mol s, k₁₁₂ = 61 L/mol s, k₂₁₂ = 1.5 L/mol s, and k₁₂₁ = 69 L/mol s. Thus, a pronounced penultimate effect was predicted in the copolymerization. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1449–1455, 1998     

Four new colchicinoids, gloriosamines A-D, from Gloriosa rothschildiana

Four new colchicinoids, gloriosamines A-D, were isolated from the aerial parts of Gloriosa rothschildiana. The structure of gloriosamine A, including the absolute configuration, was determined by chemical conversion from colchicine.     

Plant constituents biologically active to insects. VI. Antifeedants for larvae of the yellow butterfly, Eurema hecabe mandarina, in Osmunda japonica. (2)

Three antifeedants for larvae of the yellow butterfly, Eurema hecabe mandarina de l'Orza, were isolated from Osmunda japonica Thunb. and identified as osmundalin, parasorboside and methyl (3S,5S)-5-hydroxy-3-(beta-D-glucopyranosyloxy)hexanoate. In the course of isolation of the antifeedants, a new glycoside, dihydroisoosmudalin (9), was isolated together with maltol beta-D-glucopyranoside, 2-deoxy-L-ribopyranolactone, 5-hydroxymethyl.2-furfural and glycerin. The structure of 9 was elucidated as (4R,5S)-5-(beta-D-glucopyranosyloxy)hexan-4-olide on the basis of chemical and spectroscopic evidence.     

Angular distribution of different vibrational components of the X and B states reached after resonant Auger decay of core-excited H2O: experiment and theory

Vibrationally resolved spectra have been obtained for the lowest-lying cationic states X (2)B(1), A (2)A(1), and B (2)B(2) of the water molecule reached after participator resonant Auger decay of core-excited states. The angular distribution has been measured of the first four vibrational components of the X state in the photon energy regions including the O 1s-->4a(1) and the O 1s-->2b(2) core excitations, and for different portions of the vibrational envelope of the B state in the photon energy region including the O 1s-->2b(2) core excitation. For the X state, a large relative spread in beta values of the different vibrational components is observed across both resonances. For the B state, a very different trend is observed for the high binding energy side and the low binding energy side of the related spectral feature as a function of photon energy. A theoretical method based on the scattering K matrix has been used to calculate both the photoabsorption spectrum and the beta values, by taking both interference between direct and resonant photoemission and vibrational/lifetime interference into account. The numerical results show qualitative agreement with the trends detected in the experimental values and explain the conspicuous variations of the beta values primarily in terms of coupling between direct and resonant photoemission by interaction terms of different sign for different final vibrational states.     

Symmetry-resolved absorption spectra of vibrationally excited CO2 molecules

Symmetry-resolved x-ray absorption spectroscopy has been first carried out on high-temperature molecules. From the angle-resolved ion yield spectra of CO2 both at room temperature and at 430 degrees C, symmetry-resolved absorption profiles of the C 1s(-1) 2pi(u) and O 1s(-1) 2pi(u) resonances have been extracted for the vibrational ground state molecules and bending-vibration excited ones. The profiles change dramatically between them, and the Renner-Teller effect becomes more evident for the vibrationally excited molecules. The effects of the multimode vibronic coupling are suggested for the O 1s(-1) 2pi(u) and O 1s(-1) 3s sigma(g) resonances.