- A novel imidazol-2-ylidene as a ligand for palladium-catalyzed synthesis of oxyindoles from o-haloanilides
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Oxyindoles were formed in good yields from 2-bromo- or chloroanilide in the presence of a base and a novel palladium imidazol-2-ylidene complex, through a process of metal-catalyzed intramolecular arylation of amide enolates. A wide range of substrates, including electron rich aryl chlorides, were found active under the catalysis of this non-phosphinic, easily prepared ligand-metal system.
- Zhang, Tony Y,Zhang, Hongbin
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- Iron-Catalyzed Reductive Cyclization by Hydromagnesiation: A Modular Strategy Towards N-Heterocycles
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A reductive cyclization to prepare a variety of N-heterocycles, through the use of ortho-vinylanilides, is reported. The reaction is catalyzed by an inexpensive and bench-stable iron complex and generally occurs at ambient temperature. The transformation likely proceeds through hydromagnesiation of the vinyl group, and trapping of the in situ generated benzylic anion by an intramolecular electrophile to form the heterocycle. This iron-catalyzed strategy was shown to be broadly applicable and was utilized in the synthesis of substituted indoles, oxindoles and tetrahydrobenzoazepinoindolone derivatives. Mechanistic studies indicated that the reversibility of the hydride transfer step depends on the reactivity of the tethered electrophile. The synthetic utility of our approach was further demonstrated by the formal synthesis of a reported bioactive compound and a family of natural products.
- Larin, Egor M.,Lautens, Mark,Loup, Joachim
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p. 22345 - 22351
(2021/09/09)
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- Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C-H and sp3 C-H bonds
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The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a 'transition-metal-free' intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon-carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N-arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction.
- Kumar, Nivesh,Ghosh, Santanu,Bhunia, Subhajit,Bisai, Alakesh
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p. 1153 - 1169
(2016/07/06)
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- Mn(III)-based oxidative cyclization of N-aryl-3-oxobutanamides. facile synthesis and transformation of substituted oxindoles
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The oxidation of 3-oxo-N-phenylbutanamides 1 with manganese(III) acetate in ethanol afforded dimeric 3,3'-biindoline-2,2'-dione derivatives 3-5. A similar reaction of N,2-disubstituted N-aryl-3-oxobutanamides 6 in acetic acid produced 3-acetylindolin-2-ones 7 bearing various substituents in good to excellent yields. The acetylindolinones 7 were easily deacetylated by treatment using neutral alumina in diethyl ether. Both the acetylindolinones 7 and deacetylated indolinones 8 were transformed by reduction into the substituted 1H-indoles.
- Kikue, Nobutaka,Takahashi, Tetsuya,Nishino, Hiroshi
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p. 540 - 562
(2015/03/04)
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- Nickel-catalyzed aromatic C-H alkylation with secondary or tertiary alkyl-bromine bonds for the construction of indolones
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A nickel-catalyzed aromatic C-H alkylation with tertiary or secondary alkyl-Br bonds for the construction of indolones was demonstrated. Various functional groups were well tolerated. Moreover, the challenging secondary alkyl bromides were well introduced in this transformation. Radical trapping and photocatalysis conditions exhibited that it is most likely to be a radical process for this aromatic C-H alkylation.
- Liu, Chao,Liu, Dong,Zhang, Wei,Zhou, Liangliang,Lei, Aiwen
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supporting information
p. 6166 - 6169
(2014/01/17)
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- Molybdenum-catalyzed asymmetric allylic alkylation of 3-alkyloxindoles: Reaction development and applications
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We report a full account of our work towards the development of Mo-catalyzed asymmetric allylic alkylation reactions with 3-alkyloxindoles as nucleophiles. The reaction is complementary to the Pd-catalyzed reaction with regard to the scope of oxindole nucleophiles. A number of 3-alkyloxindoles were alkylated successfully under mild conditions to give products with excellent yields and good-to-excellent enantioselectivities. Applications of this method to the preparation of indoline alkaloids such as (-)-physostigmine, ent-(-)-debromoflustramine B, and the indolinoquinoline rings of communesin B are reported.
- Trost, Barry M.,Zhang, Yong
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p. 2916 - 2922
(2011/05/02)
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- Asymmetric synthesis of oxindoles containing a quaternary stereogenic centre by catalytic O/C-carboxyl rearrangement
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A catalysed O/C-carboxyl rearrangement generates the all-carbon stereogenic centre in phenyl 1,3-dimethyl-5-methoxy-2-oxoindoline-3-carboxylate (up to 57% ee). Crystallisation and removal of racemic crystals enhance the ee to 95%. The X-ray crystal struct
- Ismail, Muhammad,Nguyen, Huy V.,Ilyashenko, Gennadiy,Motevalli, Majid,Richards, Christopher J.
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scheme or table
p. 6332 - 6334
(2010/02/28)
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- Racemic N1-norphenserine and its enantiomers: Unpredicted inhibition of human acetyl- and butyrylcholinesterase and β-amyloid precursor protein in vitro
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The optically pure enantiomers of N1-norphenserine (15, 16) were synthesized and its racemate 17 was prepared by mixing equal parts of each enantiomer. (-)-N1-Norphenserine (15) was prepared by partial synthesis initiated from the natural product, (-)-physostigmine (1). (+)-N 1-Norphenserine (16) was prepared by total synthesis using the Julian oxindole route, with modifications. The in vitro inhibitory activities of 15-17 were quantified against human erythrocyte AChE and plasma BChE as well as against human neuroblastoma cell β-amyloid precursor protein secretion in cell culture. All were active. Racemic compound (17) with a high AChE and β-amyloid precursor protein inhibitory action may warrant further assessment in Alzheimer's disease models.
- Yu, Qian-Sheng,Luo, Weiming,Holloway, Harold W.,Utsuki, Tada,Perry, Tracy Ann,Lahiri, Debomoy K.,Greig, Nigel H.,Brossi, Arnold
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p. 529 - 539
(2007/10/03)
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- New asymmetric synthesis of (-)-esermethole
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A new synthesis of (-)-esermethole, based on the asymmetric alkylation at C(3) of racemic 1,3-dimethyl-5-methoxyoxindole (3), is described. The chloroacetyl derivatives of (-)-menthol and (S)-N-methyl-(1-phenylethyl) amine were chosen as chiral alkylating agents and used under different reaction conditions (temperature, solvent and base). In particular, the latter reacted with 3 in toluene at 10°C, in the presence of t-butyllitium, giving (3S,1'S)-N-methyl-N-(1'-phenylethyl)-1,3-dimethyl-5-methoxyoxindol-3-i lacetamide (10) with a 63% d.e.. This intermediate was easily separated from the undesired minor (3R,1'S) diastereomer (11) and converted to (-)-esermethole (99.6% e.e.) in two steps.
- Pallavicini,Valoti,Villa,Resta
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p. 363 - 370
(2007/10/02)
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- Synthesis and Anti-Acetylcholinesterase Activity of Thiaphysostigmine Derivatives
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A series of thiaphysostigmine derivatives (2a,b and 3a,b), with a sulfur atom instead of N-methyl group in B ring or C ring of physostigmine (1), were synthesized, and their inhibitory effects on AChE and BuChE activity, and acute toxicity were evaluated.
- An-naka, Masayuki,Yasuke, Koesuke,Yamada, Masaki,Kawai, Akiyoshi,Takamura, Norio,et al.
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p. 251 - 270
(2007/10/02)
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- Indirect Electroreductive Cyclisation of N-Allylic and N-Propargylbromo Amides and o-Bromoacryloylanilides using Nickel(II) Complexes as Electron-transfer Catalysts
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Nickel(II) complex-catalysed indirect electroreduction of N-allylic and N-propargyl-α-bromo amides and o-bromoacryloylanilides gave the corresponding 5-membered lactams.The product distribution was affected by the ability of the solvent to donate hydrogen atom.The electroreduction of N-allyl-N-(bromoacetyl)toluene-p-sulfonamide 1a in DMF and acetonitrile yielded as main product the 4-methylpyrrolidinone 2a (41percent) and the 4-(bromomethyl)pyrrolidinone 3a (33percent), respectively.On addition of 2 mol equiv. of a hydrogen-atom donor (Ph2PH) to the reaction of bromo amide 1a in acetonitrile, compound 1a provided compound 2a (58percent) as the sole cylised product.
- Ozaki, Shigeko,Matsushita, Hidenori,Ohmori, Hidenobu
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p. 2339 - 2344
(2007/10/02)
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- Utilization of chloroacetone in the synthesis of 3-methylindoles
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Synthesis of 3-methylindoles 2 and 5 are described starting from chloroacetone and the corresponding monoalkylated anilines utilizing a modified alkylation-cyclization sequence. Compound 5 was converted in high yield into a very useful oxindole 7 in two steps.
- Underwood,Prasad,Repic,Hardtmann
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p. 343 - 349
(2007/10/02)
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