- Bio-based N-alkyl-2-pyrrolidones by Pd-catalyzed reductive N-alkylation and decarboxylation of glutamic acid
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Environmental regulations boost the search for new safer and less toxic bio-based solvents to replace controversial high-boiling solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide in the chemical industry. Recently, N-alkyl-2-pyrrolidones and 5-methyl-N-alkyl-2-pyrrolidones were proposed as attractive alternative solvents for many applications. Here, we report a bio-based two-step chemocatalytic system for the synthesis of a broad range of N-alkyl-2-pyrrolidones starting from glutamic acid and C3-C5 carbonyl compounds. In the first step N-mono-alkylated derivatives of glutamic acid were synthesized in high yields (>85%) by a mild and efficient Pd-catalyzed reductive N-alkylation. Subsequently, thermally induced lactamization to the corresponding N-alkylpyroglutamic acid followed by Pd-catalyzed decarboxylation at 250 °C under inert atmosphere resulted in N-alkyl-2-pyrrolidones. Hydrolytic degradation was partially counteracted by the neutralization of the N-alkylpyroglutamic acid substrate with a base, resulting in yields up to 82%. Finally, both reaction steps were successfully combined in a one-pot process using the same Pd/Al2O3 catalyst in different conditions of gas atmosphere and temperature.
- De Schouwer, Free,Adriaansen, Sander,Claes, Laurens,De Vos, Dirk E.
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p. 4919 - 4929
(2017/10/19)
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- Fast, acid-free, and selective lactamization of lactones in ionic liquids
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(Chemical Equation Presented) A fast and acid-free one-pot 0.2-30 mmol microwave methodology for direct ionic liquid-mediated preparation of lactams from lactones and primary amines has been developed. The protocol was investigated with a wide range of primary amines and a handful of lactones, including substrates with acid-sensitive substituents. Both γ-lactams and δ-lactams were, despite the complete absence of a Bronsted acid, obtained in useful to excellent yields after only 35 min of microwave processing.
- Orrling, Kristina M.,Wu, Xiongyu,Russo, Francesco,Larhed, Mats
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supporting information; experimental part
p. 8627 - 8630
(2009/04/11)
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- Reductive O- and N-alkylations. Alternative catalytic methods to nucleophilic substitution
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Different amides have been selectively mono-N-alkylated using catalytic heterogeneous palladium and carbonyl compounds as alkylating agents. The same salt free method has been applied to the synthesis of ethers from alcohols. Reaction parameters have been studied in detail and a mechanism is proposed.
- Fache, Fabienne,Bethmont, Valerie,Jacquot, Laurent,Lemaire, Marc
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p. 231 - 238
(2007/10/03)
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- Extension of the Eschweiler-Clarke procedure to the N-alkylation of amides
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The selective N-alkylation of amides (cyclic or acyclic) under hydrogen is reported using aldehydes or ketones as alkylating agents and Pd/C/Na2SO4 as catalyst. Good isolated yields are obtained (81% to 98%).
- Fache, Fabienne,Jacquot, Laurent,Lemaire, Marc
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p. 3313 - 3314
(2007/10/02)
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- EFFICIENT SYNTHESIS OF N-SUBSTITUTED LACTAMS FROM (N-ARYLSULFONYLOXY)AMINES AND CYCLIC KETONES
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A new method is reported for the direct preparation of N-substituted lactams from cycloalkanones.N-(p-nitrobenzenesulfonoxyl) methylamine 1a (CH3NH-OSO2C6H4NO2) was reacted with a series of cycloalkanones to give good yields of N-methyl lactams.An addition-rearrangement pathway accounts for the ring-expanded lactam products.A series of N-alkyl-N-arylsulfonoxyl amines were generated in situ and reacted with cyclobutanone to give N-alkyl pyrrolidinones in high yields.
- Hoffman, Robert V.,Salvador, James M.
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p. 4207 - 4210
(2007/10/02)
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