- Polyfunctional 4-quinolinones. Synthesis of 2-substituted 3-hydroxy-4-oxo-1,4-dihydroquinolines
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We present here two new methods based on rearrangement reactions to obtain novel 2-substituted 3-hydroxy-4-oxo-1,4-dihydroquinolines, an important family of heterocycles with potential applications. Alkyl 3-hydroxy-4-oxo-1,4-dihydroquinoline-2-carboxylates were obtained by alkoxide promoted rearrangement of alkyl isatinacetates. A second synthetic route involves the alkoxide promoted reaction of both isatin and N-methylisatin, with alkylating agents having acidic methylenes. This reaction leads to the formation of spiroepoxyoxindoles via Darzens' condensation. When phenacyl bromides are used, the initially obtained benzoyl substituted spiroepoxyoxindoles were smoothly transformed into the corresponding 2-benzoyl-3-hydroxy-4-quinolinones with good to excellent yields.
- Shmidt, María S.,Perillo, Isabel A.,Camelli, Alicia,Fernández, María A.,Blanco, María M.
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p. 1022 - 1026
(2016/02/18)
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- Reaction of isatin with alkylating agents with acidic methylenes
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The reaction of isatin (1) with different alkyl halides 2 and alkaline carbonates in aprotic polar solvents leads mainly to N-alkyl derivatives 3. The use of alkylating agents that have acidic methylenes leads to competitive formation of the corresponding epoxide 5. The formation of 5 is favored by low-polarity solvents at low temperatures and strong bases. Epoxides 5c, d obtained using NaEtOH/EtOH at 0-5 °C are transformed into the corresponding 4-quinolinones 6 at higher temperatures. The use of Ag2CO3 allows obtaining compounds 3 as major products, along with varying amounts of labile O-alkyl derivatives 4 and dimerization products.
- Shmidt, María S.,Perillo, Isabel A.,González, Mercedes,Blanco, María M.
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supporting information; experimental part
p. 2514 - 2517
(2012/06/18)
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- SYNTHESIS OF 2-ARYL-3-HYDROXYQUINOLIN-4(1H)-ONES
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Eight substituted phenacyl anthranilates have been prepared by reaction of sodium anthranilate with substituted phenacyl halides in dimethylformamide in the yields from 31 to 93percent.The phenacyl esters were cyclized in polyphosphoric acid or by mere heating to give the respective substituted 2-aryl-3-hydroxyquinolin-4(1H)-ones in the yields from 77 to 98percent.All the compounds prepared have been characterized by their 1H and 13C NMR spectra.
- Hradil, Pavel,Jirman, Josef
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p. 1357 - 1366
(2007/10/02)
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