Direct Synthesis of Lactams from Keto Acids, Nitriles, and H₂ by Heterogeneous Pt Catalysts

Abstract

We report herein the first general catalytic system for the direct synthesis of N‐substituted γ‐ and δ‐lactams by reductive amination/cyclization of keto acids (including levulinic acid) with nitriles and H2 under mild conditions (7 bar H2, 110 °C, solvent free). The most effective catalyst, Pt and MoOx co‐loaded TiO2 (Pt‐MoOx/TiO2), shows a wide substrate scope, high turnover number (TON), and good reusability.

The Catalytic Reduction of Carboxylic Acid Derivatives and CO2 by Metal Nanoparticles on Lewis‐Acidic Supports

“…It has recently been discovered that Pt‐MoO X /TiO 2 selectively catalyzes the synthesis of N ‐substituted γ‐ and δ‐lactams from 1 : 1 mixtures of keto acids (including LA) and nitriles under 7 bar H 2 at 110 °C in the absence of solvents. We have studied the scope of nitriles for this catalytic reaction . Scheme shows the yields of N ‐substituted γ‐lactams ( N ‐substituted‐5‐methyl‐2‐pyrrolidones) from LA and various nitriles under 7 bar H 2 using 1 mol % Pt‐MoO X /TiO 2 .…”

Selective Transformations of Triglycerides into Fatty Amines, Amides, and Nitriles by using Heterogeneous Catalysis

“…The alarming predictions of the rapid depletion of fossil‐fuel resources have inspired researchers to develop alternative technologies that exploit renewable energy sources . Many studies have focused on the conversion of lignocellulosic biomass and triglycerides into various platforms of value‐added chemicals . Industrially, triglycerides in oils and fats have been used as feedstocks for the synthesis of fatty amines, amides, nitriles, and alcohols, which in turn are used for the production of surfactants, polymers, and other useful commodity chemicals …”

Cycloamination strategies for renewable N-heterocycles

“…Among the developed catalytic systems, noble metal catalysts (e.g., Pt/P-TiO 2 , Pt-MoO x /TiO 2 , Pt/TiO 2D , Ru/TiO 2 , Ir/SiO 2 -SO 3 H, and iridium complexes) are highly efficient for the cascade reaction process (up to 99% yield of pyrrolidones) under mild conditions (room temperature to 120°C, P(H 2 ) ≲1 MPa). [114][115][116][117][118][119][120] Apart from LA (22a) and primary amines, carbohydrates (e.g., glucose) and nitro compounds can be employed as the precursor of LA (22a) and nitrogen sources for producing pyrrolidones via additional acid-catalyzed hydrolysis and in situ hydrogenation steps, respectively. 121,122 The replacement of precious elements in Scheme 8 with abundant and low-cost metals is highly desirable, for which several well-designed base metal catalysts, such as Cu 15 /Al 2 O 3 doped with Pr (Cu 15 Pr 3 /Al 2 O 3 ), 123 carbon-supported FeNi nanoparticles, 124 and carbon nanotubes supported porous-carbon-coated Ni (CNF x @Ni@CNTs) 125 have been explored for synthesis of N-substituted pyrrolidones (up to 99% yield) from LA (22a) and amines although they require relatively harsh reaction conditions (130°C to 175°C, 1 to 5 MPa H 2 ).…”