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21.
Yoshiaki Miyamoto Norihiro Wada Dr. Takahiro Soeta Dr. Shuhei Fujinami Prof. Dr. Katsuhiko Inomata Prof. Dr. Yutaka Ukaji 《化学:亚洲杂志》2013,8(4):824-831
The stereoselective direct transformation of N‐(propargylic)hydroxylamines into cis‐2‐acylaziridines was achieved by the combined use of AgBF4 and CuCl. Copper salts were found to promote the transformation of the intermediary 4‐isoxazolines into 2‐acylaziridines and both 3‐aryl‐ and 3‐alkyl‐substituted 2‐acylaziridines could be prepared by using this method. Furthermore, subsequent 1,3‐dipolar cycloaddition of azomethine ylides that were generated in situ from the intermediary 2‐acylaziridines with maleimides was achieved in a stereoselective one‐pot procedure to afford the corresponding 2‐acylpyrrolidines, which consisted of an octahydropyrrolo[3,4‐c]pyrrole skeleton. 相似文献
22.
Alkylesters of orthophosphoric acids have been used for alkylation of phenols1, anilines2, and nitrogen heterocyclic compounds.3 However, no example is reported on their use as an alkoxylating agent for aromatic amines. We have found that alkyl phosphates can act as alkoxylating agents for aromatic diamines in the presence of H2O or aqueous H3PO4. We now report the one-step dialkoxylation of aromatic diamines such as diaminoanthracene and -naphthalene by trialkyl phosphates. 相似文献
23.
Toshiaki Yamashita Shuhei Matsushita Takuya Nagatomo Ryosuke Yamauchi Masahide Yasuda 《Research on Chemical Intermediates》2013,39(1):111-126
Photoirradiation of Me2CO–H2O solution of pent-4-en-1-ol (1a) with a high-pressure mercury lamp in a test tube gave 8-hydroxyoctan-2-one (3a) in 66 % yield along with oxetane (4a) and the isomer (4a′) in 10 % yield. Irradiation of the running Me2CO–H2O solution of 1a in the flow system of a microchannel reactor (MCR) gave mainly 4a. The photoreaction of 1,1-diphenylethene (2a) with triethylamine gave a Markovnikov-type adduct (5a) and an anti-Markovnikov-type adduct (6a). The use of the MCR enhanced the production of 5a. These phenomena were explained by the light-path length effects of the MCR. 相似文献
24.
Dr. Bernd M. Schmidt Berit Topolinski Dr. Mihoko Yamada Dr. Shuhei Higashibayashi Prof. Dr. Mitsuhiko Shionoya Prof. Dr. Hidehiro Sakurai Prof. Dr. Dieter Lentz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13872-13880
The syntheses and properties of corannulenes carrying electron‐withdrawing groups (F, CF3, C6F5) are reported. Direct fluorination of corannulene (C20H10) was carried out with xenon difluoride, and the crystal structure of the product was confirmed by the X‐ray analysis. Novel trifluoromethylated corannulenes, including the versatile 4,9‐dibromo‐1,2‐bis(trifluoromethyl)corannulene, were obtained by various established ring‐closing reactions. Besides the use of hexafluorobutyne for the construction of fluoranthenes by Diels–Alder reaction as precursor molecules to form 1,2‐disubstituted corannulenes, bis(pentafluorophenyl)acetylene was employed as dienophile. The molecular structure and crystal packing of a trifluoromethylated corannulene was determined by single‐crystal X‐ray analysis and compared with those known brominated and trifluoromethylated corannulenes. The general electron‐acceptor properties of corannulenes bearing substituents introduced in particular positions by liquid‐phase synthesis are discussed together with published computational results. 相似文献
25.
Ryan Gianatassio Shuhei Kawamura Cecil L Eprile Klement Foo Jason Ge Aaron C. Burns Michael R. Collins Phil S. Baran 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(37):10009-10013
A simple method to convert readily available carboxylic acids into sulfinate salts by employing an interrupted Barton decarboxylation reaction is reported. A medicinally oriented panel of ten new sulfinate reagents was created using this method, including a key trifluoromethylcyclopropanation reagent, TFCS‐Na. The reactivity of six of these salts towards C H functionalization was field‐tested using several different classes of heterocycles. 相似文献
26.
In this study, we achieved the first total synthesis of natural prunustatin A (1), a novel inhibitor of glucose-regulated protein 78 (GRP78) expression. A key feature included a 15-membered ring macrocyclization, which was successfully accomplished by employing Shiina macrolactonization using 2-methyl-6-nitrobenzoic anhydride (MNBA) and 4-dimethylaminopyridine (DMAP). 相似文献
27.
Shuhei Uesugi Zhao Li Dr. Ryo Yazaki Prof. Dr. Takashi Ohshima 《Angewandte Chemie (International ed. in English)》2014,53(6):1611-1615
A highly chemoselective conjugate addition of alcohols in the presence of amines is described. The cooperative nature of the catalyst enabled chemoselective activation of alcohols over amines, allowing the conjugate addition to soft Lewis basic α,β‐unsaturated nitriles. Divergent transformation of the nitrile functionality highlights the utility of the present catalysis. 相似文献
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[structure: see text] Covalently linked dimers of amphotericin B were prepared by cross-linking its carboxylic acid. Among these, a dimer with a linkage of 1,6-hexanediamine revealed potent hemolytic activity (EC50, 0.25 microM) while its N-acetyl derivative gave rise to large K+ ion flux in phosphatidylcholine liposomes, regardless of the presence or absence of sterols, suggesting that the dimers may serve as a tool for elucidating the structure of the ion channel assemblage formed by amphotericin B. 相似文献