- A Short Total Synthesis of Benzophenanthridine Alkaloids via a Rhodium(III)-Catalyzed C-H Ring-Opening Reaction
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The biologically important naturally available benzophenanthridines were prepared efficiently in three steps with overall good yields. A new synthetic methodology involving a rhodium(III) catalyzed redox-neutral ring-opening of 7-azabenzonorbornadienes with aromatic aldoximes is developed to synthesize the target molecules. The developed C-H ring-opening reaction is highly diastereoselective and compatible with various sensitive functional group substituted aromatic aldoximes as well as substituted 7-azabenzonorbornadienes. The ring-opening products were transformed into highly sensitive 13,14-dehydrobenzo phenanthridine derivatives by HCl hydrolysis. Subsequently, 13,14-dehydrobenzophenanthridines were converted into biologically important benzophenanthridine alkaloids in the presence of DDQ. A possible reaction mechanism was proposed for the C-H ring-opening reaction and supported by the deuterium labeling studies.
- Aravindan, Narasingan,Jeganmohan, Masilamani
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p. 14826 - 14843
(2021/10/20)
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- One-pot synthesis of alternating peptides exploiting a new polymerization technique based on Ugi's 4CC reaction
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We developed a one-pot synthetic technique for alternating peptides. Central to this technique is a new, catalyst-free polymerization based on Ugi's 4CC reaction. The treatment of imines with the ambident molecules bearing both an isocyanide and a carboxylic acid afforded alternating peptides.
- Koyama, Yasuhito,Gudeangadi, Prashant G.
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supporting information
p. 3846 - 3849
(2017/04/04)
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- Cyclic Hydroxamic Acid Analogues of Bacterial Siderophores as Iron-Complexing Agents prepared through the Castagnoli–Cushman Reaction of Unprotected Oximes
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The first application of multicomponent chemistry (the Castagnoli–Cushman reaction) toward the convenient one-step preparation of cyclic hydroxamic acids is described. Cyclic hydroxamic acids are close analogues of bacterial siderophores (iron-binding com
- Bakulina, Olga,Bannykh, Anton,Dar'in, Dmitry,Krasavin, Mikhail
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supporting information
p. 17667 - 17673
(2017/12/26)
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- Regiospecific synthesis of substituted 2-nitrobenzaldehydes from benzaldehydes through palladium-catalyzed chelation-assisted C-H nitration
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A regiospecific synthesis of substituted 2-nitrobenzaldehydes from substituted benzaldehydes has been developed that involves a three-step process with palladium-catalyzed chelation-assisted C-H nitration as the key step. In the process, O-methyl aldoxime serves as a removable directing group for the palladium-catalyzed ortho-nitration of substituted benzaldoximes and it can be removed in subsequent conversion of the resulting 2-nitrobenzaldoximes into 2-nitrobenzaldehydes.
- Zhang, Wei,Wu, Degui,Zhang, Jian,Liu, Yunkui
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p. 5827 - 5835
(2014/10/15)
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- Solid-phase synthesis of benzothiazoles using an alkoxyamine linker
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An alkoxyamine linker was applied for the solid-phase synthesis of benzothiazoles. The substrate was anchored by aldoxime linkage and products were cleaved from the solid-support by aldoxime-imine exchange coupled with air-oxidation under the weakly acidi
- Hioki, Hideaki,Matsushita, Kimihito,Noda, Takeshi,Yamaguchi, Kota,Kubo, Miwa,Harada, Kenichi,Fukuyama, Yoshiyasu
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scheme or table
p. 4337 - 4342
(2012/09/25)
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- Ruthenium-catalysed conversion of oxime ethers into nitriles
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The conversion of oxime ethers into nitriles has been achieved under neutral conditions using Ru(CO)(PPh3)3H2 and the bidentate ligand Xantphos as the catalyst.
- Anand, Naveen,Owston, Nathan A.,Parker, Alexandra J.,Slatford, Paul A.,Williams, Jonathan M.J.
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p. 7761 - 7763
(2008/02/12)
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- HIV Integrase inhibitors
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The present invention relates to the inhibition of HIV integrase, and to the treatment of AIDS or ARC by administering compounds of the following formula, or a tautomer of said compound, or a pharmaceutically acceptable salt, solvate or prodrug thereof: wherein R1, R2 and B1 are as defined herein.
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- Inhibition of the antibacterial target UDP-(3-O-acyl)-N-acetylglucosamine deacetylase (LpxC): Isoxazoline zinc amidase inhibitors bearing diverse metal binding groups
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UDP-3-O-[R-3-hydroxymyristoyl]-GlcNAc deacetylase (LpxC) is a zinc amidase that catalyzes the second step of lipid A biosynthesis in Gram negative bacteria. Known inhibitors of this enzyme are oxazolines incorporating a hydroxamic acid at the 4-position,
- Pirrung, Michael C.,Tumey, L. Nathan,Raetz, Christian R. H.,Jackman, Jane E.,Snehalatha, Karnem,McClerren, Amanda L.,Fierke, Carol A.,Gantt, Stephanie L.,Rusche, Kristin M.
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p. 4359 - 4370
(2007/10/03)
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- Tandem oxidation processes: The direct conversion of activated alcohols into oximes; synthesis of citaldoxime
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The direct conversion of primary alcohols into oximes is reported using manganese dioxide and alkoxylamines/hydroxylamine as their hydrochloride salts or supported on Amberlyst 15. This transformation has been applied to a range of benzylic, allylic and propargylic alcohols and utilised to prepare the natural product citaldoxime.
- Kanno, Hisashi,Taylor, Richard J. K.
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p. 1287 - 1290
(2007/10/03)
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- Stereoselective Synthesis of trans-2-Aryl-3-(2-pyridyl)aziridines from an α-Silyl Carbanion
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Five para-substituted benzaldehyde oxime O-methyl ethers (3) reacted with 2-(trimethylsilylmethyl)pyridine (1) in the presence of lithium di-isopropylamide (LDA) in tetrahydrofuran to give the corresponding trans-2-aryl-3-(2-pyridyl)aziridines (4) in high yield (80, 85, 60, 58, and 74percent, respectively), with small amounts of (Z)-1-amino-1-aryl-2-(2-pyridyl)ethenes (5), and N',N'-di-isopropylbenzamidines (7) as byproducts.The yields of compounds (4) and (5) and their ratio were considerably influenced by experimental conditions (especially molar ratio and the addition method of the reactants).When treated with LDA, compounds (3) were quantitatively converted into benzonitriles, which reacted with anion (2) to give enamines (5) after elimination of a trimethylsilyl group from the corresponding N-trimethylsilyl derivatives, or with additional LDA to give the benzamidine (7); aziridines (4) were not transformed into enamines (5) by the action of LDA.On the basis of these results, a reaction mechanism has been discussed for the formation of compounds (4).
- Konakahara, Takeo,Matsuki, Masayuki,Sugimoto, Shinji,Sato, Kenji
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p. 1489 - 1494
(2007/10/02)
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