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131.
Kinoshita H Osamura T Mizuno K Kinoshita S Iwamura T Watanabe S Kataoka T Muraoka O Tanabe G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(14):3896-3904
Reactions between chiral 3-cinnamoyl-4-methyl-5-phenyl-1,3-oxazolidine-2-thiones and aromatic aldehydes in the presence of BF3Et2O diastereoselectively produced tricyclic compounds incorporating a bridgehead carbon bound to four heteroatoms in high yields. Four stereocenters were induced during the reaction. The tricyclic products were transformed into propane-1,3-diols bearing three consecutive stereocenters by acid hydrolysis, S-methylation, and reductive removal of the chiral auxiliary. 相似文献
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133.
The reaction of ortho-alkynylphenylureas 1 having a carbamoyl group attached to the nitrogen atom proceeded in the presence of catalytic amounts of PtI4, affording corresponding indole-3-carbamides 2 in moderate to high yields. In addition, the platinum-catalyzed cyclization of ortho-alkynylphenyl carbamates 3 afforded corresponding indole-3-carboxylates 4 in good yields. The present reaction proceeds through the intramolecular addition of carbon-nitrogen bonds to triple bonds, the so-called carboamination. 相似文献
134.
We have observed the generation of sumanenylidene ( 2 ), a divalent, neutral‐carbon species at the benzylic position of sumanene ( 1 ). We also clarified both experimentally and theoretically that the ground state of compound 2 was a triplet state and that its singlet–triplet energy gap (ΔEST) was similar to that in fluorenylidene. The curved structure of compound 2 led to slightly better spin delocalization over the two adjacent aromatic rings than in planar systems, because of the unpaired spins on the σ and π orbitals. Synthetic application of the carbene precursor, diazosumanene ( 5 ), with a variety of thiocarbonyl compounds revealed its utility for the preparation of tetrasubstituted alkene compounds (e.g., that contain a strongly electron‐donating unit) that are directly conjugated to the sumanene ( 1 ) moiety. 相似文献
135.
A polyoxometalate-macrocation ionic crystal of Cs5[Cr3O(OOCH)6(H2O)3][alpha-CoW12O40].7.5H2O (1a) was synthesized by the complexion of an inorganic metal-oxide cluster of [alpha-CoW12O40]6- and a macrocation of [Cr3O(OOCH)6(H2O)3]+. About 50% of the water of crystallization in 1a was desorbed by the evacuation to form phase 1b, and the crystallinity and crystal structure was essentially maintained by the transformation. 1b adsorbed water into the solid bulk but excluded larger alcohols. 1b was easily reusable for the separation of only water in the azeotropic mixture of ethanol and water. 相似文献
136.
Aromatic acyl radicals generated from S-(4-cyano)phenyl 2-alkenylthiobenzoate by a nickel complex catalyzed electroreduction undergo 5- and 6-exo cyclization to give 1-indanone and dihydro-1-naphthalenone derivatives, respectively. 相似文献
137.
Mizugaki T Murata M Fukubayashi S Mitsudome T Jitsukawa K Kaneda K 《Chemical communications (Cambridge, England)》2008,(2):241-243
Dendron stabilised Pd nanoparticles were prepared using the self-assembly of dendrons, which could catalyze a highly selective hydrogenation of dienes and acetylenes to monoenes. 相似文献
138.
Ishida Y Kai Y Kato SY Misawa A Amano S Matsuoka Y Saigo K 《Angewandte Chemie (International ed. in English)》2008,47(43):8241-8245
139.
Matsushita S Yanai Y Fusyuku A Fujiwara Y Ikeda T Ono M Han C Ojika M Nohara T 《Chemical & pharmaceutical bulletin》2007,55(7):1077-1078
Moderate acetylation of tomatidine with anhydrous acetic acid and pyridine for 20 h at r.t., followed by pseudomerization in ice-water, gave a delta(20(22))-pseudo compound, which was then subjected to ozonolysis to provide a pregnane derivative in a total 54% yield showing neuritogenic and NGF-enhancing activities. 相似文献
140.
The crystallinity and porosity of all-inorganic dodecatungstophosphate M3PW12O40 (M=Cs, NH4, Ag, denoted as MPW) particles are controlled by the changes in the synthetic temperatures and countercations. The MPW particles can be classified into three groups by the crystallinity and porosity: (i) mesoporous "disordered" aggregates, (ii) microporous "self-organized" aggregates, and (iii) nonporous single crystals. The formation and growth mechanism of MPW particles is expressed by three steps: formation of nanocrystallites, assembly of the nanocrystallites to form aggregates, and the growth of aggregates by the attachment of nanocrystallites. The time courses of the turbidity of the synthetic solution, the concentration of the nanocrystallites, and the average particle sizes of MPW particles are well reproduced by the calculation based on the mechanism. 相似文献