Bio-based N-alkyl-2-pyrrolidones by Pd-catalyzed reductive N-alkylation and decarboxylation of glutamic acid

Abstract

Bio-based N-alkyl-2-pyrrolidones were successfully synthesized, starting from glutamic acid and simple carbonyl compounds, by Pd-catalyzed reductive N-alkylation and decarboxylation.

Protein‐Rich Biomass Waste as a Resource for Future Biorefineries: State of the Art, Challenges, and Opportunities

“…The latter solvents are categorized as “Substances of Very High Concern for Authorization” by REACH and their use should be abandoned in the chemical industry . In this context, De Vos and co‐workers extended their work to the production of N ‐alkyl‐2‐pyrrolidones from glutamic acid by a three‐step method that can be performed in aqueous media: i) Pd‐catalyzed reductive N ‐alkylation of glutamic acid with C 3 –C 5 ketones and aldehydes; ii) thermal cyclization to N ‐alkylpyroglutamic acid; iii) Pd‐catalyzed decarboxylation to N ‐alkyl‐2‐pyrrolidone (Scheme , route B) . The first step is catalyzed by Pd/C under very mild conditions (e.g., 2 mol % Pd, 2–6 equiv aldehyde or ketone, 25–70 °C, 7.5 bar H 2 , 6–48 h) to obtain the mono‐alkylated product in >85 % yield.…”

“… Transformation of glutamic acid into 2‐pyrrolidone and derivatives thereof: A) intramolecular condensation to pyroglutamic acid, followed by Pd‐catalyzed decarboxylation to 2‐pyrrolidone . B) Pd‐catalyzed reductive N ‐alkylation with carbonyl compounds, intramolecular condensation to N ‐alkylpyroglutamic acid, and Pd‐catalyzed decarboxylation to N ‐alkyl‐2‐pyrrolidone …”

Sustainable access to renewable N-containing chemicals from reductive amination of biomass-derived platform compounds

“…Nitrogen-containing compounds are extensively found in diverse bioactive molecules including peptides, alkaloids, nucleic acids and other natural products, as well as widely present in a variety of commonly used pharmaceuticals [16][17][18]. From a chemical point of view, nitrogen-containing compounds are a pivotal kind of building blocks with extensive application in the synthesis of pharmaceuticals, food additives, detergents, polymer materials and agrochemicals [19][20]. Traditionally, the synthesis of nitrogen-containing compounds has primarily relied on fossil-based feedstock, rendering more sustainable synthesis from renewable resources highly desirable [21].…”

Cycloamination strategies for renewable N-heterocycles

“…146 The simple and ecofriendly protocol of Li et al 146 may open an avenue for direct synthesis of N-(un)substituted pyrrolidones/lactams by cyclic diamination of keto acids without external hydrogen gas. Besides the above-discussed reductive amination of LA (22a) and N-containing compounds, a number of other renewed synthetic routes such as ketoamides proceeding via cascade cycli-zation and ionic hydrogenation mediated by Al(OTf ) 3 and Et 3 SiH, 147 reductive transformation of itaconic acid and NH 3 over Ru/C and H 2 , 148 reductive N-alkylation and decarboxylation of glutamic acid catalyzed by Pd/Al 2 O 3 with and H 2 , 149 and Zr-catalyzed N-acylation of lactams 150 have been explored for efficient construction of pyrrolidone-type motifs. The catalyst-free reaction system seems more sustainable and economic for producing pyrrolidones, while its reaction rate is much lower than metal-or acid-catalyzed processes.…”