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71.
Photoinduced reaction of o-ethenylaryl isocyanides with organic disulfides in the presence of diphenyl ditellurides affords the corresponding bisthiolated indole derivatives via a radical cyclization process. The cyclization can proceed at room temperature upon visible-light irradiation and exhibits good tolerance to functional groups. Several organic disulfides also can be employed for this cyclization, and the corresponding bisthiolated indole derivatives are obtained selectively. In addition, the photoinduced reaction of o-ethenylaryl isocyanides with bis(2-aminophenyl) disulfide affords tetracyclic compounds in one portion. 相似文献
72.
73.
Y. Ma S. Ajimura K. Aoki M. Dairaku Y. Y. Fu H. Fujioka T. Fukuda K. Futatsukawa K. Hosomi W. Imoto M. Kawai Y. Kakiguchi S. Kinoshita T. Koike N. Maruyama M. Mimori S. Minami Y. Miura K. Miwa Y. Miyagi T. Nagae D. Nakajima H. Noumi K. Shirotori T. Suzuki T. Takahashi T. N. Takahashi H. Tamura K. Tanida N. Terada A. Toyoda K. Tsukada M. Ukai S. H. Zhou 《The European Physical Journal A - Hadrons and Nuclei》2007,33(3):243-246
In this paper, a preliminary result from the latest hypernuclear γ -ray spectroscopy experiment (KEK-E566) is presented together
with a short discussion. The experiment was performed at the KEK-PS K6 beam line in 2005. In this experiment, the 12C(π+, K
+)12
ΛC reaction was employed to populate 12
ΛC/11
ΛB hypernuclei. A germanium detector array, Hyperball2, was constructed to detect γ -rays emitted from the hypernuclei produced.
Three hypernuclear γ -ray peaks were observed and assigned. 相似文献
74.
Takenori Mitamura 《Tetrahedron letters》2007,48(34):5953-5957
Upon visible light irradiation, highly selective thiotelluration of isocyanides bearing an electron-withdrawing group like nitro or trifluoromethyl group takes place smoothly by the use of a disulfide-ditelluride mixed system. The application of this photoinduced reaction to radical cyclization of o-vinyl and o-allyl substituted phenylisocyanides successfully leads to the formation of bisthiolated indole and quinoline derivatives, respectively, in moderate yields. 相似文献
75.
Total Synthesis of the Proposed Structure of Ardimerin,and Proposal for its Structural Revision 下载免费PDF全文
Ryota Nakayama Eva‐Maria Tanzer Takenori Kusumi Ken Ohmori Keisuke Suzuki 《Helvetica chimica acta》2016,99(12):944-960
We report the first total synthesis of the proposed structure of ardimerin, which was achieved in 14 steps starting from 2,3,4‐trimethoxybenzoic acid. The key steps include the β‐selective formation of the crucial C‐glycoside linkage and stepwise construction of the strained eight‐membered salicylide core. The synthesis revealed that the proposed structure 1 does not match the natural product. A proposal is made for reassigning the isolated natural product to the already known structure of bergenin. Interesting properties of the synthetic eight‐membered salicylides are documented, including their susceptibility toward nucleophilic ring opening and the bowl chirality. 相似文献
76.
Yasumoto K Nishigami A Aoi H Tsuchihashi C Kasai F Kusumi T Ooi T 《Chemical & pharmaceutical bulletin》2008,56(1):129-132
4,8-Dimethylnonyl sulfate (1) and 3-methyl-4E-decenyl sulfate (2) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute configuration at C4 of 1 was determined by Ohrui's method applied to alcohol 3. The absolute stereochemistry at C3 of 2 was determined by (1)H-NMR analysis of the (R)-1NMA ester of alcohol 11. 相似文献
77.
The structures of circumdatins A and B, pentacyclic alkaloids produced by Aspergillus ostianus, were revised from the previously reported betaine structures to unique oxepin ones by X-ray crystallography. The co-occurring known alkaloids, circumdatins D, E, and H, and a new compound reported here, circumdatin J, have a common framework. 相似文献
78.
Takenori Mitamura 《Tetrahedron》2008,64(42):9983-9988
Upon heating of a mixture of N,N-disubstituted aromatic selenoamides and several electron-deficient olefins in the presence of copper(0) powder, a novel deselenative cyclopropanation takes place to afford the corresponding aminocyclopropanes in good yields. When acrylonitrile is employed as an electron-deficient olefin, the aminocyclopentanation occurs in preference to the aminocyclopropanation by prolonging the reaction time. The obtained aminocyclopropane derivatives can be converted to the corresponding 1,4-dicarbonyl compounds upon treatment with 2 N HCl. 相似文献
79.
Kohei Azami Taiki Hayashi Takenori Kusumi Ken Ohmori Keisuke Suzuki 《Angewandte Chemie (International ed. in English)》2019,58(16):5321-5326
The first total synthesis of carthamin ( 3 ), a historic natural red pigment, has been achieved. The molecular structure was efficiently constructed by assembling two equivalents of the in situ generated lithiated monomers and triisopropyl orthoformate. This synthesis confirms the structure proposed in 1996. 相似文献
80.
The N‐acylsulfonamide group, known as a safety‐catch linker, has been applied to photoaffinity labeling (PAL) using a cinnamate‐type photocrosslinker to improve the efficiency of PAL‐based target identification. A bioorthogonal sulfo‐click reaction was used to stably link a photocrosslinker unit with N‐acylsulfonamide linkage to produce a photoactivatable probe without any protection. In addition, the crosslinked protein was selectively isolated with a small cinnamate tag via linkage disruption upon N‐alkylation. Furthermore, the tag moiety was photochemically converted to a stable coumarin derivative by losing a water molecule, which is a useful property in MS‐based identification. 相似文献