- Pendant Alkoxy Groups on N-Aryl Substitutions Drive the Efficiency of Imidazolylidene Catalysts for Homoenolate Annulation from Enal and Aldehyde
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Hydrogen-transfer in the tetrahedral intermediate generated from an imidazolylidene catalyst and α,β-unsaturated aldehyde forms a conjugated Breslow intermediate. This is a critical step affecting the efficiency of the NHC-catalyzed γ-butyrolactone formation via homoenolate addition to aryl aldehydes. A novel type of imidazolylidene catalyst with pendant alkoxy groups on the ortho-N-aryl groups is described. Catalyst of this sort facilitates the formation of the conjugated Breslow intermediate. Studies of the rate constants for homoenolate annulation affording γ-butyrolactones, reveal that introduction of the oxygen atoms in the appropriate position of the N-aryl substituents can increase the efficiency of imidazolylidene catalysts. Structural and mechanistic studies revealed that pendant alkoxy groups can be located close to the proton of the tetrahedral intermediate, thereby facilitating the proton transfer.
- Kyan, Ryuji,Mase, Nobuyuki,Narumi, Tetsuo,Sato, Kohei
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supporting information
p. 19031 - 19036
(2020/08/25)
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- Synthesis of Aryl-Substituted 3,3a,4,5-Tetrahydropyrrolo[1,2- A [ quinolin-1(2 H)-ones and 2,3,4,4a,5,6-Hexahydro-1 H-pyrido[1,2- A [quinolin-1-ones
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A new route to the title benzo-fused angular tricyclic amides 3,3a,4,5-tetrahydropyrrolo- A nd 2,3,4,4a,5,6-hexahydro-1 H-pyrido[1,2- A [quinolin-1-ones is reported from 1-(tert-butyl) 6-ethyl 3-oxohexanedioate and 1-(tert-butyl) 7-ethyl 3-oxoheptanedioate. Alkylation of these β-keto diesters with a series of 2-nitrobenzyl bromides followed by acid hydrolysis and decarboxylation gives ethyl 6-(2-nitrophenyl)-4-oxohexanoates and ethyl 7-(2-nitrophenyl)-5-oxoheptanoates, respectively. Reductive amination under hydrogenation conditions followed by ester hydrolysis and condensative ring closure affords the final lactam products. The reactions proceed cleanly and only two chromatographic purifications are required.
- Watts, Field M.,Bunce, Richard A.
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p. 564 - 572
(2019/01/10)
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- Rh2(II)-catalyzed selective aminomethylene migration from styryl azides
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Rh2(II)-Carboxylate complexes were discovered to promote the selective migration of aminomethylenes in β,β-disubstituted styryl azides to form 2,3-disubstituted indoles. Mechanistic data are also presented that suggest that the migration occurs stepwise before diffusion of the iminium ion.
- Kong, Chen,Jana, Navendu,Driver, Tom G.
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supporting information
p. 824 - 827
(2013/03/29)
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- Simple synthesis of 7-formyl-indole
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A simple route to 7-formyl-indole (5) is described in which appropriately functionalized o-nitrotoluenes (1) are converted to 7-hydroxymethyl-indole (4) using the Batcho-Leimgruber process. Condensation of 3-methyl-2-nitrobenzyl alcohol (1a) with N,N-dimethylformamide dimethyl acetal yields the enamine 2a, which upon catalytic hydrogenation affords 4 in 22% yield. When the hydroxyl function in 1 is protected with pivaloyl or tetrahydropyranyl group, the yields of 4 are increased to 39% and 48%, respectively. Finally, 4 is oxidized with pyridinium chlorochromate (PCC) to afford 5 in 86% yield. Copyright Taylor & Francis Group, LLC.
- Uchil, Vinod R.,Gund, Machhindra,Satyam, Apparao
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p. 1051 - 1056
(2007/10/03)
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- PROCESS FOR PRODUCING (2-NITROPHENYL)ACETONITRILE DERIVATIVE AND INTERMEDIATE THEREFOR
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The present invention lies in a process for producing a compound represented by the following formula [IV], which comprises the following steps (1) to (3), as well as in an intermediate therefor.(1) A step which comprises reacting a compound represented by the following formula [I] with a compound represented by the following formula [VI] or with a mixture of a compound represented by the following formula [VII] and a compound represented by the following formula [VIII] to obtain a compound represented by the following formula [IX], and hydrolyzing the compound represented by the formula [IX] under acidic conditions to obtain a compound represented by the following formula [II].(2) A step which comprises reacting the compound represented by the formula [II] with hydroxylamine to obtain a compound represented by the following formula [III].(3) A step which comprises dehydrating the compound represented by the formula [III] to obtain a compound represented by the formula [IV].
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- TRICYCLIC QUINOXALINEDIONE DERIVATIVES
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A tricyclic quinoxalinedione derivative represented by the formula 1: STR1 wherein X represents hydrogen, alkyl, halogen, cyano, trifluoromethyl, or nitro;R 1 represents hydrogen, alkyl, cycloalkyl, or cycloalkylalkyl;G represents--CONR 2--or--NR 2 CO--, wherein R 2 represents hydrogen or alkyl;J represents an acidic group or a group which is convertible thereto in vivo;E represents an basic group or a group which is convertible thereto in vivo;Y represents a single bond, alkylene, alkenylene, substituted alkylene, or Y 1--Q--Y 2, wherein Y 1 represents a single bond or alkylene, Y 2 represents alkylene, and Q represents a heteroatom selected from oxygen or sulfur;Z represents alkylene, or a pharmaceutically acceptable salt thereof, these compounds are selective antagonists of glycine binding site of the NMDA receptor.
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