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981.
982.
Adler S Atiya MS Chiang IH Frank JS Haggerty JS Kycia TF Li KK Littenberg LS Sambamurti A Stevens A Strand RC Witzig C Louis WC Akerib DS Ardebili M Convery MR Ito MM Marlow DR McPherson RA Meyers PD Selen MA Shoemaker FC Smith AJ Blackmore EW Bryman DA Felawka L Kitching P Konaka A Kujala VA Kuno Y Macdonald JA Nakano T Numao T Padley P Poutissou JM Poutissou R Roy J Soluk R Turcot AS 《Physical review letters》1996,76(9):1421-1424
983.
Orita A Hamada Y Nakano T Toyoshima S Otera J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(15):3321-3327
Deprotection of acetyl esters is effected cleanly by the neutral organotin catalyst, [tBu2SnOH(Cl)]2. The mildness of the reaction gives rise to great synthetic versatility and in the process a variety of functional groups are tolerated. Differentiations between primary, secondary, and tertiary alcohols and between acetyl ester and other esters are feasible. No racemization occurs with chiral acetyl esters. Exclusive deprotection of primary acetyl esters in carbohydrates and nucleosides is observed. The crude product thus obtained can be used for further reactions without purification. 相似文献
984.
New sterols and triterpenoids from four edible mushrooms 总被引:1,自引:0,他引:1
Yaoita Y Matsuki K Iijima T Nakano S Kakuda R Machida K Kikuchi M 《Chemical & pharmaceutical bulletin》2001,49(5):589-594
Four edible mushrooms, Panellus serotinus, Lepista nuda, Tricholoma matsutake and Naematoloma sublateritium, have been investigated chemically. Two new sterols, 5alpha,9alpha-epidioxy-(22E)-ergosta-7,22-diene-3beta,6alpha-diol (1) and 5alpha,9alpha-epidioxy-(22E)-ergosta-7,22-diene-3beta,6beta-diol (2), have been isolated from Panellus serotinus. Compound 2 was also isolated from Lepista nuda. A new sterol, 3beta,5alpha,9alpha,14beta-tetrahydroxy-(22E)-ergosta-7,22-dien-6-one (3), and compound 2 have been isolated from Tricholoma matsutake. Three new triterpenoids, sublateriols A-C (4-6), have been isolated from Naematoloma sublateritium. The structures of the new compounds were elucidated on the basis of their spectral data. 相似文献
985.
The transfer rates of theophylline and phenobarbital from blood into the peritoneal cavity were investigated after their intravenous administrations at a dose of 10 mg/kg each in rats. Appreciable amounts of both drugs were transported into the dialysate with their transfer rates decreasing as the serum concentrations declined. The average amount of theophylline transferred into the dialysate was 17% and 24% of dose in 2 and 4 h, respectively, while that of phenobarbital was 13% and 45% of dose in 2 and 8 h, respectively. The amounts appeared to be greater than those transported into the intestinal lumen which was previously reported by the authors. Peritoneal dialysis decreased the serum half-life and the area under the serum concentration-time curve (AUC) value of theophylline from 2.1 to 1.5 h and from 38 to 26 micrograms.h/ml, respectively and increased the total body clearance by 47% as compared with the control. The dialysis also decreased the serum half-life and the AUC value of phenobarbital from 8.3 to 5.3 h and from 116 to 83 micrograms.h/ml, respectively and increased the total body clearance by 112% as compared with the control. Overall, the effectiveness of peritoneal dialysis in removing theophylline and phenobarbital appears to be not very different from that of intestinal dialysis with oral activated charcoal which has been previously reported by the authors in spite of the difference in transport into the intestinal lumen and peritoneum. 相似文献
986.
Nakano K Sada K Kurozumi Y Miyata M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(1):209-220
The crystal structures of inclusion compounds of cholic acid (CA) with 28 monosubstituted benzenes have been systematically investigated. All of the crystals belong to the monoclinic space group P2(1) and have bilayer structures with one-dimensional molecular channels that can include guest compounds. They are classified into four types of host frameworks that depend on the conformations and stacking modes of the host compound. The host frameworks and the host-guest ratios depend primarily on the molecular volumes of the guest compounds. The packing coefficient of the host cavity (PCcavity), which is the volume ratio of the guest compound to the host cavity, is used to clarify the relationship between the guest volume and isomerization of the host frameworks. The value of PCcavity, for stable inclusion compounds lies in the range of 55-70%. Compounds out of this range induce isomerization of the host frameworks. The packing coefficients of other host-guest compounds, in which the guest components are included in the host cavities through steric dimensions and van der Waals forces, are also in this range. These results indicate that PCcavity is a useful parameter correlation for guest recognition and isomerization of the host frameworks. 相似文献
987.
Kotaro?Yokoyama Haruyuki?Nakano Kimihiko?HiraoEmail author James P.?Finley 《Theoretical chemistry accounts》2003,110(3):185-189
Maximum radius of convergence (MAXR
c) perturbation theory [(2000) Journal of Chemical Physics 112:6997] is tested on the beryllium and neon atoms using calculations that are truncated in high orders. Calculations are also performed on the ground-state potential-energy curves of H2 and HF. The neon atom calculations use the 3-21G basis set with added diffuse s and p functions. All other calculations use the STO-3G minimum basis set. MAXR
c perturbation theory consistently performs well. The Epstein–Nesbet and Møller–Plesset perturbative expansions frequently diverge or exhibit slow convergence compared to the expansions obtained from MAXR
c.
AcknowledgementsJ.P. Fi. acknowledges support for a grant from the Japanese Society for the Promotion of Science.Contribution to the Björn Roos Honorary Issue 相似文献
988.
We prepared iminodiacetic acid (IDA)-modified and Cu(II)-IDA-modified capillaries through polymerization of N-(vinylbenzylimino) diacetic acid. The fundamental performance of these capillaries was examined in capillary liquid chromatography (LC) and immobilized metal chelate affinity capillary electrophoresis (IMACE). Copper(II), cobalt(II), and hematin were detected at different retention times by means of capillary LC with a chemiluminescence detector, during which the IDA-modified capillary was used. The difference in the retention times was attributed to the difference in the interaction between metal ions or complex and IDA moieties on the inner wall of the capillary. In addition, human serum albumin (HSA) and human serum gamma-globulin (HgammaG) were separated and detected using IMACE with an absorption detector, during which the Cu(II)-IDA-modified capillary was used. The separation of HSA and HgammaG was achieved through the interaction between proteins and Cu(II) chelate moieties on the inner wall of this capillary. 相似文献
989.
The interactions between seven anionic azo dyes and hen egg-white lysozyme were investigated by means of visible absorption spectroscopic and lytic activity measurements. The dyes, for which no report on the interaction has appeared so far, were bound with lysozyme to different extents as a result of the differences in their chemical structures. Although most of the dyes formed 11 complex with lysozyme, two of them behaved differently. From the measurements of the absorption, lytic inhibition toward cell walls and competitive binding with substrate analogues, it was concluded that a major binding site of these dyes on lysozyme is a charged lysine residue in the vicinity of the subsitesD, E andF, and, in the case of a dye that forms 21 complex with lysozyme, and additional binding site is in the vicinity of the subsite B. 相似文献
990.
T. Takeuchi Y. Nakano S. Ohmori A. Aoki M. Kasuya 《Journal of Radioanalytical and Nuclear Chemistry》1990,144(2):97-106
To investigate the present situation of inhabitants living in the cadmium polluted area of Toyama Prefecture of Japan, 95 hair samples were analyzed by neutron activation method. The median and the geometric standard deviation were determined from a cumulative frequency distribution curve of the elemental concentrations for each of 3 groups: male, female without perm and female with perm which were divided furthermore by two age ranges: 20 age<50 and 50 age. These concentrations were compared with those in some organs and urine reported. 相似文献