- A New Method for the Synthesis of 3-Substituted Indoles
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Starting from readily accessible nitrones and electron-deficient acetylenes, a highly efficient and versatile synthetic protocol for 3-substituted indoles has been developed.
- Natarajan, Rakesh,Rappai, John P.,Unnikrishnan, Peruparampil A.,Radhamani, Sandhya,Prathapan, Sreedharan
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supporting information
p. 2467 - 2471
(2015/10/19)
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- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
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The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
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p. 9898 - 9905
(2013/10/22)
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- Simple, fast and efficient synthesis of β-keto esters from the esters of heteroaryl compounds, its antimicrobial study and cytotoxicity towards various cancer cell lines
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A series of β-keto esters were synthesized from heteroaryl esters and ethyl acetate using LiHMDS as base at -50 to -30 °C. The increase in yields of cross condensed product were observed and the percentage of self condensed product was reduced drastically by applying the suitable base (LiHMDS), solvent and the minimum amount of ethyl acetate. All these β-keto esters were characterized using 1H NMR, 13C NMR and mass spectral data. A plausible mechanism is also depicted to prove the formation of trans-esterified products. All the synthesized compounds were subjected to test for their cytotoxicity towards various cancer cell lines and also tested for their antimicrobial activity towards various bacterial and fungal strains and some of them were found to have promising activity.
- Venkat Ragavan,Vijayakumar,Rajesh,Palakshi Reddy,Karthikeyan,Suchetha Kumari
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supporting information; experimental part
p. 4193 - 4197
(2012/07/14)
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- A dipolar cycloaddition approach toward the kopsifoline alkaloid framework
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Using a metal-catalyzed domino reaction as the key step, the heterocyclic skeleton of the kopsifoline alkaloid family was constructed by a 1,3-dipolar cycloaddition of a carbonyl ylide dipole derived from a Rh(II)-catalyzed reaction of a diazo ketoester across the indole π-bond. Ring opening of the resulting 1,3-dipolar cycloadduct followed by a reductive dehydroxylation step resulted in the formation of a critical silyl enol ether necessary for the final F-ring closure of the kopsifoline skeleton.
- Hong, Xuechuan,France, Stefan,Padwa, Albert
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p. 5962 - 5976
(2008/02/07)
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- Unexpected products from the Fp2-catalyzed reductive cyclization of nitroaromatics bearing pendant unsaturation
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A representative o-nitroenone (Z=O) was cyclized by reduction with CO and [CpFe(CO)2]2 (Fp2) as the catalyst to give the corresponding 4-quinolone. In contrast, Baylis-Hillman adducts derived from o-nitrobenzaldehydes were
- O'Dell, David K.,Nicholas, Kenneth M.
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p. 747 - 754
(2007/10/03)
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- Imidoylketene-oxoketenimine interconversion. Rearrangement of a carbomethoxyketenimine to a methoxyimidoylketene and 2-methoxy-4-quinolone
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FVP of triazole 13 produces the isolable ketenimine 11 together with indole 15. 11 undergoes reversible interconversion with imidoylketene 10 above 380 °C. The latter cyclizes to quinolone 12. Meldrum's acid derivative 16 produces the same ketene 10 above 200 °C, and the latter isomerizes to ketenimine 11 at 200 °C by a 1,3-shift of a MeO group. A competing elimination of MeOH from 16 produces (phenylimino)propadienone 20.
- Fulloon, Belinda E.,Wentrup, Curt
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p. 1363 - 1367
(2007/10/03)
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- (Cyanovinyl)ketenes from azafulvenones. An apparent retro-Wolff rearrangement
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Flash vacuum pyrolyses or pulsed pyrolysis of azole esters 1b and 20 and their carboxylic acids 1a and 19 or acid chloride 1c give five-membered ring ketenes (azafulvenones) 2 and 24 which dimerize to diketopiperazines 3 and 21 but also undergo efficient
- Qiao,Meutermans,Wong,Traubel,Wentrup
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p. 3852 - 3861
(2007/10/03)
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- Photolysis of 1-Aryl-1,2,3-triazoles; Rearrangement via !H-Azirines
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The preparation and photolysis of a series of 1-(1-naphthyl)-1,2,3-triazoles, (2)-(5), and of 1-(2-methyl-1-naphthyl)-1,2,3-triazoles, (6)-(9), with and without electron-withdrawing groups (CO2R, CONH2, CN, CHO, COPh) in the triazole ring, are described.In the first series, triazoles (3) with two electron-withdrawing groups, and triazoles (4) with one such group at C-4, mostly give good yields of the expected benzindoles (10) and 11 respectively.Triazoles (5) with the electron-withdrawing group at C-5 also give benzindoles but these are now mixtures of the expected (12) and rearranged indoles (11).Photolysis of the 1-phenyltriazoles (21) and (22) follows the same pattern, those with the electron-withdrawing group at C-5 rearranging to give mixtures of indoles (23) and (24).This is explained by a mechanism (Scheme 3) in which the less stable carbene intermediate (13) rearranges to the more stable carbene (15) via the 1H-azirine (14), in competition with its direct cyclisation.This provides the first evidence for antiaromatic 1H-azirines as intermediates in a photochemical reaction.Photolysis of the 2-methylnaphthyl compounds follows a different path: diester (7b) and dinitrile (7d) give high yields of the deeply coloured 9-methyl-1H-benzoquinoline derivatives (25a) and (25b) respectively, the first stable examples of this ring system to be isolated.Photolysis of the nitrile (8c) gives 9b-methyl-9bH-benzindole-3-carbonitrile (28), a rare example of a stable indole with a ring junction substituent. 1,2-Shifts in the carbenes are only observed with the bis(trimethylsilyl)triazoles (2d) and (6f), in keeping with the known rapid migration of trimethylsilyl groups to carbene centres.
- Mitchell, Glynn,Rees, Charles W.
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p. 413 - 422
(2007/10/02)
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- 1H-Azirines as Intermediates in the Photolysis of 1,2,3-Triazoles
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Photolytic conversion of 1-aryl-1,2,3-triazoles (5) and (14) into the 'rearranged' indoles (4) and (15), respectively, provides the first evidence for antiaromatic 1H-azirines, e.g. (8), as reactive intermediates in a photochemical reaction.
- Mitchell, Glynn,Rees, Charles W.
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p. 399 - 401
(2007/10/02)
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