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91.
We show that given any closed subset C of a real Banach space E, there is a continuous function f(t, x) which is Lipschitz continuous in its second variable such that the solution set of the corresponding third kind boundary value problem is homeomorphic to C (Theorem 1.1). In the special problem we give the infimum of Lipschitz constants Lf of such functions f(t, x) (Theorem 1.3). 相似文献
92.
Disposition of ipriflavone (TC-80) in rats and dogs 总被引:1,自引:0,他引:1
K Yoshida T Tsukamoto H Torii T Doi I Naeshiro K Shibata I Uemura S Tanayama 《Radioisotopes》1985,34(11):618-623
Oral 14C-ipriflavone was absorbed by rats to give a maximum plasma 14C level at 1.5 h and a half-life of 5.8 h. In dogs, after po dosing, the plasma 14C peaked at 0.5 h, followed by gradual decline. The plasma of both animals contained mostly metabolites, with small amounts of unchanged ipriflavone. In rats, 14C was distributed widely in tissues, with relatively high concns. in the liver, kidney and gut. Distribution in rat thigh bone of unmetabolized ipriflavone was also demonstrated. 14C-Ipriflavone was eliminated mostly as metabolites within 48 and 72 h, respectively, in rats and dogs. Rats excreted more 14C in urine than in feces, whereas the reverse was noted in dogs. Biliary excretion and reabsorption of 14C were also obvious in both animals. 相似文献
93.
By the reaction of α-methylaldehydes with trimethylsilylethylidenetriarylphosphoranes the introduction of vinyl group is effected in highly Cram-selective manner. 相似文献
94.
Kitamura M Tsukamoto M Bessho Y Yoshimura M Kobs U Widhalm M Noyori R 《Journal of the American Chemical Society》2002,124(23):6649-6667
The mechanism of asymmetric hydrogenation of alpha-(acylamino)acrylic esters with Ru(CH(3)COO)(2)[(S)-binap] (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), giving the S saturated products in >90% ee, has been investigated by means of a kinetic study, deuterium labeling experiments, isotope effect measurements, and NMR and X-ray analysis of certain Ru complexes. The hydrogenation in methanol under a low H2 pressure proceeds via a monohydride-unsaturate mechanism that involves the initial RuH formation followed by a reaction with an olefinic substrate. The migratory insertion in the enamide-RuH chelate complex occurs reversibly and endergonically in an exo manner, giving a five-membered metallacycle intermediate. The cleavage of the Ru-C bond is achieved with either H2 (major) or CH3OH (minor). Both of the pathways result in overall cis hydrogenation products. The hydrogen at C3 is mainly from an H2 molecule, and the C2 hydrogen is from another H2 or protic CH3OH. The major S and minor R enantiomers are produced via the same mechanism involving diastereomeric intermediates. The turnover rate is limited by the step of hydrogenolysis of a half-hydrogenated metallacyclic intermediate. The participation of two different hydrogen donor molecules is in contrast to the pairwise dihydrogenation using a single H2 molecule in the RhI-catalyzed reaction which occurs via a dihydride mechanism. In addition, the sense of asymmetric induction is opposite to that observed with S-BINAP-RhI catalysts. The origin of this phenomenon is interpreted in terms of stereocomplementary models of the enamide/metal chelate complexes. A series of model stoichiometric reactions mimicking the catalytic steps has indicated that most NMR-observable Ru complexes are not directly involved in the catalytic hydrogenation but are reservoirs of real catalytic complexes or even side products that retard the reaction. 相似文献
95.
Dr. Masahito Yoshida Dr. Koya Saito Dr. Hikaru Kato Prof. Dr. Sachiko Tsukamoto Prof. Dr. Takayuki Doi 《Angewandte Chemie (International ed. in English)》2018,57(18):5147-5150
The total synthesis of siladenoserinol A, an inhibitor of the p53–Hdm2 interaction, has been achieved. AuCl3‐catalyzed hydroalkoxylation of an alkynoate derivative smoothly and regioselectively proceeded to afford a bicycloketal in excellent yield. A glycerophosphocholine moiety was successfully introduced through the Horner–Wadsworth–Emmons reaction using an originally developed phosphonoacetate derivative. Finally, removal of the acid‐labile protecting groups, followed by regioselective sulfamate formation of the serinol moiety afforded the desired siladenoserinol A, and benzoyl and desulfamated analogues were also successfully synthesized. Biological evaluation showed that the sulfamate is essential for biological activity, and modification of the acyl group on the bicycloketal can improve the inhibitory activity against the p53–Hdm2 interaction. 相似文献
96.
97.
[reaction: see text] Two new and very efficient procedures (Procedures A and B) are reported for the Pd-catalyzed cross coupling of aryl electrophiles with terminal alkynes via their in situ conversion into alkynylzinc derivatives. Procedure A is particularly valuable in cases where electron-deficient alkynes are used, while Procedure B is operationally simple and very satisfactory in less demanding cases. 相似文献
98.
Summary A manual method for predicting the detection ranges of fluorescent compounds for the HPLC-peroxyoxalate chemiluminescence
detection system is presented utilizing bis(4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl) oxalate (TDPO) as a chemilumigenic
reagent. The generated chemiluminescence decay curves were measured on a photomultiplier and extrapolated to zero time based
on the first part of the decay curve. Dipyridamole, perylene, DNS-Ser, Rose Bengal, DNS-Asp, Trp-P-1, pyrencarboxylic acid
methyl ester, perfenazine, alimemazine, oxypertine, Glu-P-2, benzydamine and doxorubicin gave chemiluminescence intensity
(Icl) values of 3.2 × 106, 2.8 × 106, 2.3 × 105, 2.1 × 105, 1.9 × 105, 1.4 × 105, 9.4 × 103, 6.2 × 103, 4.2 × 103, 3.3 × 103, 2.3 × 103, 9.7 × 102 and 3.1 × 102, respectively. The reaction conditions for the HPLC-CL detection system were investigated and optimum conditions obtained. 相似文献
99.
K. Fuke K. Tsukamoto F. Misaizu 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(Z1):204-206
Photoionization thresholds of Si
n
(n=2–40) were examined by vacuum UV radiation (5.7–8.5 eV) generated by stimulated Raman scattering of narrow-bandwidth 193-nm radiation in high pressure hydrogen and deuterium gases. A strong threshold energy dependence on cluster size is observed, featuring major maxima at 10 and 20. The magic behavior atn=10 is consistent with the results of the photofragmentation and CID experiments reported previously. 相似文献
100.