- Biomimetic total synthesis of malbrancheamide and malbrancheamide B
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(Chemical Equation Presented) The biomimetic total syntheses of both malbrancheamide and malbrancheamide B are reported. The synthesis of the two monochloro species enabled the structure of malbrancheamide B to be unambiguously assigned. The syntheses each feature an intramolecular Diels-Alder reaction of a 5-hydroxypyrazin-2(1H)-one to construct the bicyclo[2.2.2] diazaoctane core, which has also been proposed as the biosynthetic route to these compounds.
- Miller, Kenneth A.,Welche, Timothy R.,Greshock, Thomas J.,Ding, Yousong,Sherman, David H.,Williams, Robert M.
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- Efficient electrochemical cleavage of N,N-dimethylaminosulfonyl-protected indoles
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Indoles protected at the N-1 position with the N,N-dimethylaminosulfonyl group were efficiently deprotected by electrolysis. Yields were in the 80-90% range and the method was compatible with a number of functional groups (nitrile, ester, chloride, carboxamide). (C) 2000 Elsevier Science Ltd.
- Largeron,Farrell,Rousseau,Fleury,Potier,Dodd
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- Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
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Herein, we report a facile method for the synthesis of Ni-NiO heterojunction nanoparticles, which we utilized for the nuclear halogenation reaction of phenol and substituted phenols usingN-bromosuccinimide (NBS). A remarkablepara-selectivity was achieved for the halogenated products under semi-aqueous conditions. Interestingly, blocking of thepara-position of phenol offeredortho-selective halogenation. In addition, the Ni-NiO nanoparticles catalyzed the oxidative esterification of carbonyl compounds with alcohol, diol or dithiol in the presence of a catalytic amount of NBS. It was observed that the aromatic carbonyls substituted with an electron-donating group favoured nuclear halogenation, whereas an electron-withdrawing group substitution in carbonyl compounds facilitated the oxidation reaction. In addition, the catalyst was magnetically separated and recycled 10 times. The tuned electronic structure at the Ni-NiO heterojunction controlled selectivity and activity as no suchpara-selectivity was observed with commercially available NiO or Ni nanoparticles.
- Bhardwaj, Nivedita,Singh, Ajit Kumar,Tripathi, Nancy,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.
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p. 14177 - 14183
(2021/08/16)
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- PhI(OAc)2/NaX-mediated halogenation providing access to valuable synthons 3-haloindole derivatives
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This paper describes a mild phenyliodine diacetate mediated method for selective chlorination, bromination, and iodination of indole C-H bonds using sodium halide as a source for analogous halogenations. The combination of NaX and phenyliodine diacetate provides an invincible system for halogenation of indoles. This protocol was compatible with a wide array of indole substrates and provides straight forward access to potential halogenated arenes.
- Himabindu, Vittam,Parvathaneni, Sai Prathima,Rao, Vaidya Jayathirtha
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p. 18889 - 18893
(2018/11/27)
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