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81.
6A,6X-Dideoxy-6A-phenylthio-6X-[(β-naphthylsulfonyl)oxyl]-β-cyclodextrins (X=G and B) (5 and 6) were prepared together with the other isomers (X=C, D, E, and F) (1–4), isolated by reversed-phase column chromatography, and structurally assigned by use of Taka amylolysis. 相似文献
82.
Daisuke Mori Atsuo Yamada Masaki Azuma Katsumi Suda 《Journal of solid state chemistry》2006,179(3):935-940
Single crystals of the thallium ruthenium pyrochlore have been grown by flux method under high oxygen pressure. The growth conditions were determined by direct observations using in situ powder X-ray diffraction (XRD) method under high pressure and high temperature. The crystals were grown using NaCl-KCl flux at 1350 °C and B2O3 flux at 1150 °C. High growth temperature of 1350 °C for the NaCl-KCl flux caused Pt contamination from the crucible and oxygen deficiency for the crystals obtained. The crystal growth using B2O3 flux proceeded at lower temperature by grain growth with material transfer through B2O3. The crystal obtained was characterized by single-crystal XRD method, and was found to have a stoichiometric composition, Tl2Ru2O7−δ (δ=0), with a structural phase transition around 120 K. The grain growth technique with B2O3 is efficient for high-temperature single-crystal growth under high pressure. 相似文献
83.
84.
Kiyoshi Bannai Takeshi Toru Takeo
ba Toshio Tanaka Noriaki Okamura Kenzo Watanabe Atsuo Hazato Seizi Kurozumi 《Tetrahedron》1986,42(24):6735-6746
Syntheses of several stable PGI2 analogs substituted by halogen atoms(s) at C-5 or(and) C-7 are described. Reaction of protected PGI2 methyl ester (
) with
-chlorosuccinimide gave 5-chloro-Δ6-PGI1 derivative (
), which was transformed into 5-chloro- and 5,7-dichloro-PGI2 [(
) and (
)] by subsequent isomerization or chlorination. Similarly, reaction of
with
-bromosuccinimide gave 5-bromo-Δ6-PGI1 derivative (
), which was further transformed into 7-fluoro-PGI2 (
) by silver fluoride treatment. These halogenated PGI2 analogs were found to be much more stable than PGI2. 相似文献
85.
Atom-centered partial charges which exactly reproduce the lowest several multipoles of a molecule's charge distribution can be obtained in a straightforward and convenient manner from the output of existing electronic structure calculations. The multipole constraint method is demonstrated by a computation of partial charges for the twenty common amino acids. The electron density employed here, derived from a semiempirical MNDO calculation, incorporates Slater-type orbitals which imbue it with the exponential fall-off vital to electronic tunneling calculations. In addition, a procedure based on these charges is described which divides the original electron density into two components, a large component with a simple electrostatic potential, and a much smaller residual whose several lowest multipoles vanish. 相似文献
86.
A Divergent Approach to the Diastereoselective Synthesis of 3,3‐Disubstituted Oxindoles from Atropisomeric N‐Aryl Oxindole Derivatives 下载免费PDF全文
Dr. Atsuo Nakazaki Ayako Mori Prof. Dr. Susumu Kobayashi Prof. Dr. Toshio Nishikawa 《化学:亚洲杂志》2016,11(22):3267-3274
3,3‐Disubstituted oxindoles were divergently synthesized by diastereoselective transformations including nucleophilic addition, alkylation, and cycloaddition using common, axially chiral N‐aryl oxindoles. Notably, high diastereoselectivities (up to >95:5) were observed with ortho‐monosubstituted N‐aryl oxindoles to give various oxindole scaffolds, and facile removal of the p‐(benzyloxy)aryl moiety in axially twisted amides was achieved by a mild, two‐step sequence. 相似文献
87.
The aim of the present study was to mask the bitterness of propiverine hydrochloride (P-4) by converting it to propiverine free base. Fine granules comprising the free base, which was converted from P-4 by desalination, were prepared. By using Fourier transform infrared spectroscopy, thermogravimetry-differential thermal analysis, and powder X-ray diffraction spectra, we confirmed that P-4 had been converted into propiverine free base by desalination during the manufacturing process. Furthermore, the conversion into free base appeared to result in decreased solubility, and both the taste testing sensor and tasting volunteers determined that it masked the bitterness of P-4. On using the gustatory sensation test, the bitterness of the P-4 fine granules was confirmed to be weakened. The dissolution rate and bioavailability of fine granules of the free base were compared with tablets of P-4. The dissolution rate and bioavailability of the fine granules and tablets were almost the same. We successfully masked the taste of P-4 by converting it into free base using a manufacturing process that was suitable for commercial manufacturing. 相似文献
88.
Hori K Sadatomi H Miyamoto A Kuroda T Sumimoto M Yamamoto H 《Molecules (Basel, Switzerland)》2010,15(11):8289-8304
This study describes an attempt to develop a synthetic route using theoretical calculations, i.e., in silico synthesis route development. The KOSP program created four potential synthetic routes for generating 2,6-dimethylchroman-4-one. In silico screening of these four synthetic routes was then performed. In silico screening involves theoretical analysis of synthetic routes prior to actual experimental work. A synthetic route using the Mitsunobu reaction had already been reported by Hoddgets et al. Theoretical investigations were also conducted on two S(N)Ar reactions as well as a Michael reaction before they were examined experimentally. In silico screening using DFT calculations indicated that only the Michael reaction was likely to produce the target. Experimental work confirmed that the target was obtained in a yield of 76.4% using the Michael reaction. The other two routes, except for the Mitsunobu reaction, failed to generate the target. Our results demonstrate that theoretical calculations can be used to narrow down the number of experiments that need to be conducted when developing novel synthetic routes. 相似文献
89.
Daisuke Sato Koya Yamashiro Hideaki Onishi Yoshimitsu Shimoyama Takuya Yoshida Atsuo Maruyama 《BMC neuroscience》2012,13(1):13
Background
Water immersion therapy is used to treat a variety of cardiovascular, respiratory, and orthopedic conditions. It can also benefit some neurological patients, although little is known about the effects of water immersion on neural activity, including somatosensory processing. To this end, we examined the effect of water immersion on short-latency somatosensory evoked potentials (SEPs) elicited by median nerve stimuli. Short-latency SEP recordings were obtained for ten healthy male volunteers at rest in or out of water at 30°C. Recordings were obtained from nine scalp electrodes according to the 10-20 system. The right median nerve at the wrist was electrically stimulated with the stimulus duration of 0.2 ms at 3 Hz. The intensity of the stimulus was fixed at approximately three times the sensory threshold. 相似文献90.