616-45-5

Oxidation of cis or trans 1,5-diazadecalin with (PhIO)n yields 2-pyrrolidinone and not 1,6-diaza-2,7-cyclodecadione, as reported. This is shown by a comparison of the NMR data of the reaction product with those of 2-pyrrolidinone and 1,6-diaza-2,7-cyclodecadione.

Atomically precise gold cluster catalysts have emerged as a new frontier in catalysis science, owing to their unexpected catalytic properties. In this work, we explore the evolution of the catalytic activity of clusters formed by the structural fusion of icosahedral Au13 units, namely Au25(SR)18, Au38(SR)24, and Au25(PPh3)10(SC2H4Ph)5Cl2, in the oxidation of pyrrolidine to γ-butyrolactam. We demonstrate that the structural fusion of icosahedral Au13 units, forming vertex-fused (vf), face-fused (ff), and body-fused (bf) clusters, can induce a decrease in the catalytic activity in the following order: Aubf > Auff > Auvf. The structural fusion of icosahedral Au13 units in the clusters does not distinguish the adsorption modes of pyrrolidine over the three clusters from each other, but modulates the chemical adsorption capacity and electronic properties of the three clusters, which is likely to be the key reason for the observed changes in catalytic reactivity. Our results are expected to be extendable to study and design atomically defined catalysts with elaborate structural patterns, in order to produce desired products.

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Glutamic acid, an abundant nonessential amino acid, was converted into 2-pyrrolidone in the presence of a supported Ru catalyst under a pressurized hydrogen atmosphere. This reaction pathway proceeded through the dehydration of glutamic acid into pyroglutamic acid, subsequent hydrogenation, and the dehydrogenation–decarbonylation of pyroglutaminol into 2-pyrrolidone. In the conversion of pyroglutaminol, Ru/Al2O3 exhibited notably higher activity than supported Pt, Pd, and Rh catalysts. IR analysis revealed that Ru can hydrogenate the formed CO through dehydrogenation–decarbonylation of hydroxymethyl groups in pyroglutaminol and can also easily desorb CH4 from the active sites on Ru. Furthermore, Ru/Al2O3 showed the highest catalytic activity among the tested catalysts in the conversion of pyroglutamic acid. Consequently, the conversion of glutamic acid produced a high yield of 2-pyrrolidone by using the supported Ru catalyst. This is the first report of this one-pot reaction under mild reaction conditions (433 K, 2 MPa H2)? which avoids the degradation of unstable amino acids above 473 K.

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Herein, we report the isolation and a reactivity study of the first example of an elusive palladium(II) terminal imido complex. This scaffold is an alleged key intermediate for various catalytic processes, including the amination of C?H bonds. We demonstrate facile nitrene transfer with H?H, C?H, N?H, and O?H bonds and elucidate its role in catalysis. The high reactivity is due to the population of the antibonding highest occupied molecular orbital (HOMO), which results in unique charge separation within the closed-shell imido functionality. Hence, N atom transfer is not necessarily associated with the high valency of the metal (PdIII, PdIV) or the open-shell character of a nitrene as commonly inferred.

We have synthesized compounds: N-(2-aminoacetyl)-2-pyrrolidone (1) and N-(2-aminoacetyl)-2-piperidone (2). When these compounds are dissolved in aprotic or protic solvents a fast equilibrium ca. 1:1 between the cyclol form (tetrahedral intermediate) and the bislactam macrocycle is established. The same result has been reported previously for N-(2-aminoacetyl)-2-caprolactam (3). For compounds 2 and 3, dynamic 1H-NMR (using the methylene signals α to the carbonyl and to the amino group) through spectrum simulation has been used to evaluate the exchange between the two mentioned forms at different pH. However, for compound 1 the exchange was evaluated using magnetization transfer technique. The more stable bislactam configuration of the macrocycle form in compounds 2 and 3, is the trans-cis (one lactam with the cyclic alkyl chains trans oriented and the other cis oriented). However, the same form for compound 1 has a more stable cis-cis bislactam configuration. This difference in configuration induces substantial changes in the appearance of the methylene 1H-NMR signals that precludes the use of line-shape analysis to evaluate the rates. The rate law for the proposed mechanism of exchange between the cyclol form and the macrocycle is: K = [macrocycle]/[cyclol] =kobs.f/kobs.r = Kak2[H2O]/[H+]/k-2Kw /[H+] = Kak2[H2O]/k-2Kw; where Ka is the acidity equilibrium constant of the cyclol form, Kw = 10-14 M2 and k2 and k-2 are the second order rate constants for the specific exchange catalysis. Therefore, both, the macrocycle formation (kobs.f) and the cyclol formation (kobs.r) are specific base catalyzed; however the equilibrium constant is independent of pH. Since K is ca. 1, the δG≠ associated with the measured rate constants represent the intrinsic barrier for this non-identical thermoneutral transformation where a cleavage of a tetrahedral intermediate is involved. The activation energies associated with the reverse rate constants then correspond to the intrinsic barrier for transannular cyclolization.

Kinetics of formation of thermolysis products in heating of thin films of poly-N-vinylpyrrolidone and of poly-N-vinylpyrrolidone with covalently bound fullerene C60 was studied by thermal desorption mass spectrometry.

The catalytic aerobic α-oxidation of amines in water is an atom economic and green alternative to current methods of amide synthesis. The reaction uses O2 as terminal oxidant, avoids hazardous reactants and gives water as the only byproduct. Here we report that the catalytic activity of silica-supported Au nanoparticles for the aerobic α-oxidation of amines can be improved by tethering pyridyl ligands to the support. In contrast, immobilization of thiol groups on the material gives activities comparable to Au supported on bare silica. Our studies indicate that the ligands affect the electronic properties of the Au nanoparticles and thereby determine their ability to activate O2 and mediate C-H cleavage in the amine substrate. The reaction likely proceeds via an Au catalyzed β-hydride elimination enabled by backdonation from electron-rich metal to the orbital. O2, which is also activated on electron-rich Au, acts as a scavenger to remove H from the metal surface and regenerate the active sites. The mechanistic understanding of the catalytic conversion led to a new approach for forming C-C bonds α to the N atoms of amines.

The present disclosure provides compounds and methods useful for inhibiting SARM1 and/or treating and/or preventing axonal degeneration.

We report a highly atom-efficient integrated cofactor/co-product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω-amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ?-caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole-cell biocatalysts. This cascade could be an alternative for bio-based production of ω-amino acids and corresponding lactam compounds.

Peptide bond formation is a challenging, environmentally and economically demanding transformation. Catalysis is key to circumvent current bottlenecks. To date, many homogeneous catalysts able to provide synthetically useful methods have been developed, while heterogeneous catalysts remain largely restricted to the studies addressing the prebiotic formation of peptides. Here, the catalytic activity of Zr6-based metal-organic frameworks (Zr-MOFs) toward peptide bond formation is investigated using dipeptide cyclization as a model reaction. Unlike previous catalysts, Zr-MOFs largely tolerate water, and reactions are carried out under ambient conditions. Notably, the catalyst is recyclable and no additives to activate the COOH group are necessary, which are common limitations of previous methods. In addition, a broad reaction scope tolerates substrates with bulky and Lewis basic groups. The reaction mechanism was assessed by detailed mechanistic and computational studies and features a Lewis acid activation of carboxylate groups by Zr centers toward amine addition in which an alkoxy ligand on adjacent Zr sites assists in lowering the barrier of key proton transfers. The proposed concepts were also used to study the formation of intermolecular peptide bond formation. While intrinsic challenges associated with the catalyst structure and water removal limit a more general intermolecular reaction scope under current conditions, the results suggest that further design of Zr-MOF catalysts could render these materials broadly useful as heterogeneous catalysts for this challenging transformation.

Lactams are cyclic amides that are indispensable as drugs and as drug candidates. Conventional lactamization includes acid-mediated and coupling-agent-mediated approaches that suffer from narrow substrate scope, much waste, and/or high cost. Inexpensive, less-wasteful approaches mediated by highly electrophilic reagents are attractive, but there is an imminent risk of side reactions. Herein, a methods using highly electrophilic triphosgene in a microflow reactor that accomplishes rapid (0.5–10 s), mild, inexpensive, and less-wasteful lactamization are described. Methods A and B, which use N-methylmorpholine and N-methylimidazole, respectively, were developed. Various lactams and a cyclic peptide containing acid- and/or heat-labile functional groups were synthesized in good to high yields without the need for tedious purification. Undesired reactions were successfully suppressed, and the risk of handling triphosgene was minimized by the use of microflow technology.

The production of monomers from bio-based platform chemicals shows great potential to reduce the chemical industry's demand for fossil resources. We herein present a two-step approach, which yields N-vinyl-2-pyrrolidone monomers from bio-based carboxylic acids, such as itaconic and levulinic acid. A highly active, heterogeneous palladium catalyst facilitating the reductive amidation of itaconic acid (TOF = 950 molPyr·molPd-surface-1 h-1) as well as the reductive amination of levulinic acid (TOF = 4000 molPyr·molPd-surface-1 h-1) was designed. Especially the reductive amidation of itaconic acid to 3- and 4-methyl-2-pyrrolidone was found to be structure sensitive. A clear trend between Pd particle size and catalyst activity could be shown by the synthesis of Pd/C catalysts with varying Pd particle sizes. The vinylation of the synthesized methyl-2-pyrrolidones with acetylene was tested using common industrial conditions (10-18 bar acetylene, 150 °C, KOH catalyst, no solvent). Similar to the industrial vinylation of 2-pyrrolidone, good yields of up to 80% N-vinyl-methyl-2-pyrrolidone were received. Therefore, and due to the excellent maximum yield of methyl-2-pyrrolidones in reductive amidation (95 mol%), the envisioned process can be a promising drop-in technology, directly replacing fossil resources in the production of an established monomer class. This journal is

Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.

Temporary directing groups (TDGs) underpin a range of C-C bond activation methodologies; however, the use of TDGs for the regiocontrolled activation of cyclopropane C-C bonds is underdeveloped. In this report, we show how an unusual ring contraction process can be harnessed for TDG-based carbonylative C-C bond activations of cyclopropanes. The method involves the transient installation of an isocyanate-derived TDG, rather than relying on carbonyl condensation events as used in previous TDG-enabled C-C bond activations.

A simple, safe, and inexpensive amide bond formation directly from nonactivated carboxylic acids and free amines is presented in this work. Readily available Zr(IV)- and Hf(IV)-substituted polyoxometalates (POM) are shown to be catalysts for the amide bond formation reaction under mild conditions, low catalyst loading, and without the use of water scavengers, dry solvents, additives for facilitating the amine attack, or specialized experimental setups commonly employed to remove water. Detailed mechanistic investigations revealed the key role of POM scaffolds which act as inorganic ligands to protect Zr(IV) and Hf(IV) Lewis acidic metals against hydrolysis and preserve their catalytic activity in amide bond formation reactions. The catalysts are compatible with a range of functional groups and heterocycles useful for medicinal, agrochemical, and material chemists. The robustness of the Lewis acid-POM complexes is further supported by the catalyst reuse without loss of activity. This prolific combination of Zr(IV)/Hf(IV) and POMs inaugurates a powerful class of catalysts for the amide bond formation, which overcomes key limitations of previously established Zr(IV)/Hf(IV) salts and boron-based catalysts.

The invention discloses a method for synthesizing nevacetam intermediate 2-pyrrolidone, which includes reacting 4-halogenated butyryl chloride with carbamate under the action of a catalyst to obtain 2-pyrrolidone; 1) mixing 4-halogenated butyryl chloride, catalyst and solvent A under protective gas, raising the temperature to 100-125 DEG C, raising the pressure to 3-5 atmospheric pressure, and dropping the solution of carbamate and solvent B for 40-60min, after the end of the reaction, continuing to react for 5-7h under the maintenance condition, raising the temperature to 135-160 DEG C, raising the pressure to 5-7 atmospheric pressure, reacting for 6-8h, then cooling to 40-60 DEG C and dropping to normal pressure, dripping alkali water for 20-30min, raising the temperature to 120-140 DEGC, reacting for 3-6h, raising the temperature to 140-160 DEG C, raising the pressure to 7-10 atmospheric pressure and reacting for 4-6h to the end, 2) pouring the product into 3-4 times volume of water after cooling, extracting and stratifying by adding solvent C, concentrating and evaporating the solvent to obtain the product after washing and drying of the organic layer. The method for synthesizing nevacetam intermediate 2-pyrrolidone has the advantages of low cost and high yield.

The sustainable production of polymers from biogenic platform chemicals shows great promise to reduce the chemical industry's dependence on fossil resources. In this context, we propose a new two-step process leading from dicarboxylic acids, such as succinic and itaconic acid, to N-vinyl-2-pyrrolidone monomers. Firstly, the biogenic acid is reacted with ethanolamine and hydrogen using small amounts of water as solvent together with solid catalysts. For effective conversion, the optimal catalyst (carbon supported ruthenium) has to hold the ability of activating H2 as well as (imide) CO bonds. The obtained products, N-(2-hydroxyethyl)-2-pyrrolidones, are subsequently converted in a continuous gas phase dehydration over simple sodium-doped silica, with excellent selectivity of above 96 mol% and water as the sole by-product. With a final product yield of ≥72 mol% over two process steps and very little waste due to the use of heterogeneous catalysis, the proposed route appears promising-commercially as well as in terms of Green Chemistry.

Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.

Direct oxidation of α-CH2 group of free amines is hard to achieve due to the higher reactivity of amine moiety. Therefore, oxidation of amines involves the use of sophisticated metallic reagents/catalyst in the presence or absence of hazardous oxidants under sensitive reaction conditions. A novel method for direct C-H oxygenation of aliphatic amines through a metal-free activation of molecular oxygen has been developed. Both activated and unactivated free amines were oxygenated efficiently to provide a wide variety of amides (primary, secondary) and lactams under operationally simple conditions without the aid of metallic reagents and toxic oxidants. The method has been applied to the synthesis of highly functionalized amide-containing medicinal drugs, such as O-Me-alibendol and -buclosamide.

A mild calcium catalysed Beckmann rearrangement has been realised, which forgoes the more traditional harsh reactions conditions associated with the transformation. The catalyst system is shown to be tolerant towards a wide variety of functional groups relevant to natural product synthesis and medicinal chemistry and the synthetic utility of the reaction has also been investigated. A preliminary mechanistic investigation was performed to understand the nature of the incoming nucleophile and a possible reaction pathway is described.

The ammonium-peroxycarboxylic acid mesylates derived from γ-aminobutyric acid, β-alanine, and β-piperidinopropionic acid were synthesized and characterized by spectroscopic methods and X-ray crystallography. To study the nucleophilic reactivities of the corresponding ammonium- and amino-peroxycarboxylates, the kinetics of their reactions with a series of benzhydrylium ions (Ar2CH+) were investigated in alkaline, aqueous solutions at 20 °C. Using sequential-mixing stopped-flow UV/Vis photometry, the rates of the reactions of the short-lived nucleophiles with Ar2CH+ were determined and analyzed by the linear free energy relationship lg k = sN(N + E) furnishing nucleophilicity parameters (N, sN) of the peroxycarboxylates. Quantum chemical calculations indicate that the reactivity of the zwitterionic ammonium-peroxycarboxylates is attenuated by intramolecular N–H···O hydrogen bonding.

The invention provides a preparation method for preparing 2-pyrrolidone through pyroglutamic acid. The method comprises the following steps: heating (L or D or DL) pyroglutamic acid (II) in proper solvent (Solvent) and proper catalyst (Cat.) under certain temperature condition to realize decarboxylation; and separating and distilling through general methods to obtain the 2-pyrrolidone (I); the rawmaterial (L or D or DL) pyroglutamic (II) can be prepared by dehydrating and separating (L or D or DL) glutamic acid or can be directly used in subsequent decarboxylation without being separated. Themethod has the advantages of being simple to operate, high in yield, low in cost, easy to obtain raw material, and high in product purity. The formula sees the description.

The dehydrogenative oxidation of cyclic amines catalyzed by a diruthenium complex and mechanistic studies are described. Cyclic amines and water reacted in the presence of Cp?Ru(μ-H)4RuCp? (1) (Cp? = 1,2,4-tri-tert-butylcyclopentadienyl) to afford lactams accompanied by elimination of the hydrogen gas. The reaction of hexamethylenimine with 1 at 160 °C afforded Cp?Ru(μ-H)2(μ-C6H11N)RuCp? (2), having a novel μ-cyclic imine ligand through N-H and C-H bond cleavages. Further C-H bond cleavage of 2 proceeded at 180 °C to afford Cp?Ru(μ-H)(μ-η2:η2-C6H10N)RuCp? (4), having a perpendicularly coordinated imidoyl ligand. Complex 4 readily reacted with water and liberated -caprolactam. The cooperative interaction of the two ruthenium atoms leading to N-H and double C-H bond cleavages was the key to the dehydrogenative oxidation of cyclic amines.

Heterogeneous metal complex catalysts for direct C-H activation with high activity and durability have always been desired for transforming raw materials into feedstock chemicals. This study described the design and synthesis of one-dimensional organosilica nanotubes containing 2,2′-bipyridine (bpy) ligands in the framework (BPy-NT) and their post-synthetic metalation to provide highly active and robust molecular heterogeneous catalysts. By adjusting the ratios of organosilane precursors, very short BPy-NT with ～50 nm length could be controllably obtained. The post-synthetic metalation of bipyridine-functionalized nanotubes with [IrCp?Cl(μ-Cl)]2 (Cp? = η5-pentamethylcyclopentadienyl) and [Ir(cod)(OMe)]2 (cod = 1,5-cyclooctadiene) afforded solid catalysts, IrCp?-BPy-NT and Ir(cod)-BPy-NT, which were utilized for C-H oxidation of heterocycles and cycloalkanes as well as C-H borylation of arenes. The cut-short nanotube catalysts displayed enhanced activities and durability as compared to the analogous homogeneous catalysts and other conventional heterogeneous catalysts, benefiting from the isolated active sites as well as the fast transport of substrates and products. After the reactions, a detailed characterization of Ir-immobilized BPy-NT via TEM, SEM, nitrogen adsorption, UV/vis, XPS, and 13C CP MAS NMR indicated the molecular nature of the active species as well as stable structures of nanotube scaffolds. This study demonstrates the potential of BPy-NT with a short length as an integration platform for the construction of efficient heterogeneous catalytic systems for organic transformations.

Organic azides are readily reduced to the corresponding amines by treatment with sodium iodide in the presence of acidic ion exchange resin. The process, optimal when performed at 40 °C and 200 mbar pressure on a rotatory evaporator, is extremely efficient, clean, and tolerant of a variety of functional groups.

The present invention provides for a genetically modified host cell capable of producing a lactam comprising a 2-pyrrolidone synthase, or an enzymatically active fragment thereof, heterologous to the host cell.

The present invention relates to novel manganese complexes and their use, inter alia, for homogeneous catalysis in (1) the preparation of imine by dehydrogenative coupling of an alcohol and amine; (2) C-C coupling in Michael addition reaction using nitriles as Michael donors; (3) dehydrogenative coupling of alcohols to give esters and hydrogen gas (4) hydrogenation of esters to form alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di- lactones), or polyesters); (5) hydrogenation of amides (including cyclic dipeptides, lactams, diamide, polypeptides and polyamides) to alcohols and amines (or diamine); (6) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (7) dehydrogenation of secondary alcohols to ketones; (8) amidation of esters (i.e., synthesis of amides from esters and amines); (9) acylation of alcohols using esters; (10) coupling of alcohols with water and a base to form carboxylic acids; and (11) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. (12) preparation of amides (including formamides, cyclic dipeptides, diamide, lactams, polypeptides and polyamides) by dehydrogenative coupling of alcohols and amines; (13) preparation of imides from diols.

A [RuH(CO)(py-NP)(PPh3)2]Cl (1) catalyst is found to be effective for catalytic transformation of primary alcohols, including amino alcohols, to the corresponding carboxylic acid salts and two molecules of hydrogen with alkaline water. The reaction proceeds via acceptorless dehydrogenation of alcohol, followed by a fast hydroxide/water attack to the metal-bound aldehyde. A pyridyl-type nitrogen in the ligand architecture seems to accelerate the reaction.

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.

Fe2O3/Al-MCM-41 nanocomposite catalysts were designed and fabricated to upgrade microalgae hydrothermal liquefaction (HTL)-derived biocrude and its model compounds (palmitic acid and glutamic acid) in the absence of hydrogen. The Fe

The late-stage oxidation of substituted pyrrolidines offers good flexibility for the construction of γ-lactam libraries, and especially in recent years the methods for functionalization of pyrrolidine have been available. We reported a new strategy for oxidation of pyrrolidines to γ-lactams: reaction of pyrrolidine with an o-benzoquinone gives an N,O-acetal by direct oxidation of the α-C-H bond of the pyrrolidine ring, and then the N,O-acetal is further oxidized by the o-benzoquinone to the γ-lactam. Because the first oxidation occurs selectively at the α-C-H of the pyrrolidine ring, oxidation-sensitive functional groups (allyl-, vinyl-, hydroxyl-, and amino groups) on pyrrolidine ring are unaffected. The synthetic utility of this novel method was demonstrated by the facile syntheses of (S)-vigabatrin and two analogues.

Abstract: The oxidative transformation of cyclic amines to lactams, which are important chemical feedstocks, is efficiently catalyzed by CeO2-supported gold nanoparticles (Au/CeO2) and Aerosil 200 in the presence of an atmosphere of O2. The complete conversion of pyrrolidine was achieved in 6.5?h at 160 °C, affording a 97 % yield of the lactam product 2-pyrrolidone (γ-butyrolactam), while 2-piperidone (δ-valerolactam) was synthesized from piperidine (83 % yield) in 2.5?h. Caprolactam, the precursor to the commercially important nylon-6, was obtained from hexamethyleneimine in 37 % yield in 3?h. During the oxidation of pyrrolidine, two transient species, 5-(pyrrolidin-1-yl)-3,4-dihydro-2H-pyrrole (amidine-5) and 4-amino-1-(pyrrolidin-1-yl)butan-1-one, were observed. Both of these compounds were oxidized to 2-pyrrolidone under catalytic conditions, indicating their role as intermediates in the reaction pathway. In addition to the reactions of cyclic secondary amines, Au/CeO2 also efficiently catalyzes the oxidation of N-methyl cyclic tertiary amines to the corresponding lactams at 80 and 100 °C. Graphical Abstract: [Figure not available: see fulltext.]

Although the α-oxygenation of amines is a highly attractive method for the synthesis of amides, efficient catalysts suited to a wide range of secondary and tertiary alkyl amines using O2as the terminal oxidant have no precedent. This report describes a novel, green α-oxygenation of a wide range of linear and cyclic secondary and tertiary amines mediated by gold nanoparticles supported on alumina (Au/Al2O3). The observed catalysis was truly heterogeneous, and the catalyst could be reused. The present α-oxygenation utilizes O2as the terminal oxidant and water as the oxygen atom source of amides. The method generates water as the only theoretical by-product, which highlights the environmentally benign nature of the present reaction. Additionally, the present α-oxygenation provides a convenient method for the synthesis of18O-labeled amides using H218O as the oxygen source.

Catalysts prepared from abundant, cost effective metals, such as cobalt, nickel, chromium, manganese, iron, and copper, and containing one or more neutrally charged ligands (e.g., monodentate, bidentate, and/or polydentate ligands) and methods of making and using thereof are described herein. Exemplary ligands include, but are not limited to, phosphine ligands, nitrogen-based ligands, sulfur-based ligands, and/or arsenic-based ligands. In some embodiments, the catalyst is a cobalt-based catalyst or a nickel-based catalyst. The catalysts described herein are stable and active at neutral pH and in a wide range of buffers that are both weak and strong proton acceptors. While its activity is slightly lower than state of the art cobalt-based water oxidation catalysts under some conditions, it is capable of sustaining electrolysis at high applied potentials without a significant degradation in catalytic current. This enhanced robustness gives it an advantage in industrial and large-scale water electrolysis schemes.

Amino acids have huge potential as platform chemicals in the biobased industry. Pd-catalyzed decarboxylation is a very promising route for the valorization of these natural compounds derived from protein waste or fermentation. We report that the highly abundant and nonessential amino acid L-proline is very reactive in the Pd-catalyzed decarboxylation. Full conversions are obtained with Pd/C and different Pd/MeOx catalysts; this allowed the identification of the different side reactions and the mapping of the reaction network. Due to the high reactivity of pyrrolidine, the selectivity for pyrrolidine was initially low. By carefully modifying Pd/ZrO2 with Pb in a controlled mannervia two incipient wetness impregnation stepsthe selectivity increased remarkably. Finally, a thorough investigation of the reaction parameters resulted in an increased activity of this modified catalyst and an even further enhanced selectivity under a low H2 pressure of 4 bar at 235 °C in water. This results in a very selective and sustainable production route for the highly interesting pyrrolidine.

The invention discloses a production method of a single nitrogenous heterocyclic ring-containing compound. Lactone and fatty amine which are cheap and easy to obtain are used as raw materials for producing the single nitrogenous heterocyclic ring-containing compound; lactone and fatty amine are used for synthesis of amide, and hydrodeoxygenation is carried out in order to obtain the corresponding nitrogenous heterocyclic compound. The process has only two reaction steps, and has the advantages of low investment, high yield, simple separation for intermediate products, few by-products, and easy processing.

Water-soluble prodrug strategy is a practical alternative for improving the drug bioavailability of sparingly-soluble drugs with reduced drug efficacy. Many water-soluble prodrugs of sparingly-soluble drugs, such as the phosphate ester of a drug, have been reported. Recently, we described a novel water-soluble prodrug based on O–N intramolecular acyl migration. However, these prodrug approaches require a hydroxy group in the structure of their drugs, and other prodrug approaches are often restricted by the structure of the parent drugs. To develop prodrugs with no restriction in the structure, we focused on a decomposition reaction of arginine methyl ester. This reaction proceeds at room temperature under neutral conditions, and we applied this reaction to the prodrug strategy for drugs with an amino group. We designed and synthesized novel prodrugs of representative sparingly soluble drugs phenytoin and sulfathiazole. Phenytoin and sulfathiazole were obtained as stable salt that were converted to parent drugs under physiological conditions. Phenytoin prodrug 3 showed a short half-life (t1/2) of 13?min, whereas sulfathiazole prodrug 7 had a moderate t1/2of 40?min. Prodrugs 3 and 7 appear to be suitable for use as an injectable formulation and orally administered drug, respectively.

The mechanism of the unique lactam formation from amines and water with concomitant H2 liberation with no added oxidant, catalyzed by a well-defined acridine-based ruthenium pincer complex was investigated in detail by both experiment and DFT calculations. The results show that a dearomatized form of the initial complex is the active catalyst. Furthermore, reversible imine formation was shown to be part of the catalytic cycle. Water is not only the oxygen atom source but also acts as a cocatalyst for the H2 liberation, enabled by conformational flexibility of the acridine-based pincer ligand. (Figure Presented).

The use of selected engineered galactose oxidase (GOase) variants for the oxidation of amino alcohols to aldehydes under mild conditions in aqueous systems is reported. GOase variant F2 catalyses the regioselective oxidation of N-carbobenzyloxy (Cbz)-protected 3-amino-1,2-propanediol to the corresponding α-hydroxyaldehyde which was then used in an aldolase reaction. Another variant, M3-5, was found to exhibit activity towards free and N-Cbz-protected aliphatic and aromatic amino alcohols allowing the synthesis of lactams such as 3,4-dihydronaphthalen-1(2H)-one, 2-pyrrolidone and valerolactam in one-pot tandem reactions with xanthine dehydrogenase (XDH) or aldehyde oxidase (PaoABC).

An integrated structure has been designed by grafting the polymer of polybromopyrroles (PPBP) onto reduced graphene oxide (RGO) to produce RGO/PPBP nanocomposites with superior electrochemical performance for supercapacitors. The RGO/PPBP nanocomposites are featured with a high nitrogen content (>9 at%), enhanced degree of graphitization, improved specific surface area, abundant micropores, and a tunable hierarchical structure on the basis of sample characterization by XRD, Raman, FT-IR, XPS, SEM, high-resolution TEM, BET, and scanning probe microscopy (SPM) techniques. The grafting of PPBP onto RGO not only suppresses agglomeration and restacking of RGO but also tailors the growth of PPBP on RGO, producing a developed hierarchical structure beneficial for mass/charge transfer. The synergistic effect between RGO and PPBP ensures superior electrochemical performance of RGO/PPBP. In a three-electrode mode, the typical RGO/PPBP electrode presents a galvanostatic capacitance (Cg) of 256 F g-1 at a current density of 10 A g-1, with a capacitance retention of 99.2% after 10000 cycles in 1 mol L-1 H2SO4. More significantly, the typical RGO/PPBP&3Verbar;RGO/PPBP supercapacitor cell exhibits a high Ccell value of 68 F g-1 at 5 A g-1, with a capacitance retention of 91.9% after 10000 cycles. Also, relatively high energy density values of 13.6, 9.4, and 6.7 W h kg-1 with the corresponding power density of 0.5, 2.5, and 10 kW kg-1 are achieved, enabling the tested cell to stay at the high level for carbon-based supercapacitors with an aqueous electrolyte.

In order to recycle nitrogen from nitrogen-rich waste streams, particularly protein waste, we studied the decarboxylation of pyroglutamic acid and glutamic acid in a one-pot reaction to bio-based 2-pyrrolidone. After the screening of a wide range of supported Pd and Pt catalysts, 5 wt% Pd/Al2O3 displayed the highest yield (70%) and selectivity (81%) for the decarboxylation of pyroglutamic acid in water at 250°C and under an inert atmosphere. Side products originate from consecutive reactions of 2-pyrrolidone; different reaction pathways are proposed to explain the presence of degradation products like propionic acid, γ-hydroxybutyric acid, γ-butyrolactone and methylamine. An extensive study of the reaction parameters was performed to check their influence on selectivity and conversion. This heterogeneous catalytic system was successfully extended to the conversion of glutamic acid.

Cotton bleaching is traditionally carried out in strongly alkaline solution of hydrogen peroxide (H2O2) at temperatures close to the boil. Such harsh processing conditions can result in extensive water and energy consumptions as well as severe chemical damage to textiles. In this study, an activated peroxide system was established for low-temperature cotton bleaching by incorporating a bleach activator, namely N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC) into an aqueous H2O2 solution. Experimental results showed that the TBBC-activated peroxide system exhibited the most effective bleaching performance in a pH range of 6-8 which could be approximated by adding sodium bicarbonate (NaHCO3). The TBBC/H2O2/NaHCO3 system led to rapid bleaching of cotton at a temperature as low as 50°C. In comparison with the hot alkaline peroxide bleaching system, the TBBC/H2O2/NaHCO3 system provided cotton fabric with an equivalent degree of whiteness, higher degree of polymerization, and slightly lower water absorbency. The new activated peroxide system may provide a more environmentally benign approach to cotton bleaching.

Direct conversion of cyclic amines to lactams utilizing water as the only reagent is catalyzed by pincer complex 2. In contrast to previously known methods of amine-to-amide conversion, this reaction occurs in the absence of oxidants and is accompanied by liberation of H2, with water serving as a source of oxygen atom. Formation of a cyclic hemiaminal intermediate plays a key role in enabling such reactivity. This represents an unprecedented, conceptually new type of amide formation reaction directly from amines and water under oxidant-free conditions.

Bromide-assisted electrochemical decarboxylation efficiently produces valuable nitriles in high yields from a wide range of naturally occurring amino acids in a single step. Bromide salts are used as both redox mediators and supporting electrolytes in a simple one-compartment setup. As demonstrated for lysine, the selectivity of the decarboxylation can be tuned towards nitriles, amines or amides. An electrochemical system is developed that allows the selective decarboxylation of a wide range of amino acids. Valuable nitriles are obtained in high yields in a single step by using bromide salts as both redox mediators and supporting electrolytes. The product selectivity of lysine can be tuned towards nitriles, amines, or amides.

The solubility of titanium and aluminium alcoholates and of titanium tetrakis(trimethylsilanolate) in several hexaalkylguanidinium-based room temperature ionic liquids was screened. The solvent/solute combinations which displayed the highest alcoholate solubility and stability were applied as Lewis-acidic catalytic media for several dehydrating cyclocondensations: lactamisation of ω-aminocarboxylic acids, direct amidation of carboxylic acids, synthesis of oxazolines from carboxylic acids and 2-aminoethanol, lactonisation of 6-hydroxyhexanoic acid, and Paal-Knorr synthesis of pyrroles.

Supported platinum catalysts have been studied for the reductive amination of levulinic acid (LA) by H2 to N-alkyl-5-methyl-2-pyrrolidones under solvent-free conditions. The activity depends on the type of metal (Pt, Re, Pd, Rh, Ru, Cu, Ni), support material, and coloaded oxides of transition metals (V, Cr, Mo, W, Re). In 24 kinds of catalyst tested, Pt and MoOX (molybdenum oxide) coloaded TiO2 (Pt-MoOX/TiO2) shows the highest activity. Pt-MoOX/TiO2 is effective for reductive amination of LA with wide varieties of amines under mild conditions (3 bar of H2, 100 °C, solvent-free) to give high isolated yield of pyrrolidinones and shows higher turnover number (TON) than previously reported catalysts for reductive amination of LA with an aliphatic amine. The catalyst can be separated from the reaction mixture by filtration, and the recovered catalyst can be reused. This is the first general and reusable heterogeneous catalytic system for the reductive amination of LA. On the basis of mechanistic studies, high activity of Pt-MoOX/TiO2 can be attributed to acid-base interaction between the acid sites of Pt-MoOX/TiO2 and carboxyl groups in LA and an intermediate.

The present invention relates to a method of producing bio-based homoserine lactone and bio-based organic acid through hydrolysis of O-acyl homoserine produced by a microorganism in the presence of an acid catalyst. According to the present invention, O-acyl homoserine produced by a microorganism is used as a raw material for producing 1,4-butanediol, gamma-butyrolactone, tetrahydrofuran and the like, which are industrially highly useful. The O-acyl homoserine produced by a microorganism can substitute conventional petrochemical products, can solve environmental concerns, including the emission of pollutants and the exhaustion of natural resources, and can be continuously renewable so as not to exhaust natural resources.

By employing an amination catalyst, previously used in the direct synthesis of amines from alcohol with ammonia, n-amino-alcohols could be selectively cyclized to either the amide or the amine. By the addition of water, the amine could be produced as the major product whereas adding a sacrificial ketone as a hydrogen acceptor resulted in the amide as the major product. Without an additive a mixture of both the amine and the amide was observed. N-substituted amino-alcohols solely gave cyclic amines under these conditions. From 2-(n-alkanol) anilines the cyclic amines were produced, where the n-propanol derivative selectively formed quinoline as the major product.

A wider investigation into the synthesis of secondary amides from primary alcohols using a hydrogen acceptor using commercially available [Ru(p-cymene)Cl2]2 with bis(diphenylphosphino)butane (dppb) as the catalyst. The report looks at over 50 examples with varying functionality and steric bulk, whilst also covering the first reported results using microwave heating to effect the transformation.

Treatment of [Ru2(CO)4(CH3CN)6](BF4)2 with 3-methyl-1-(pyridin-2-yl)-imidazolium bromide in the presence of tetrabutylammonium bromide at room temperature in dichloromethane affords a RuII-N-heterocyclic carbene-carbonyl complex [Ru(py-NHC)(CO)2Br2] (1). Catalyst 1 displays diverse substrate scope for phosphine-free acceptorless coupling between alcohols and amines to amides at low catalyst loading. A RuII-dihydride/Ru0 sequence is proposed in the catalytic cycle.

The hydrogenation of N-unsubstituted cyclic imides to the corresponding cyclic amines has been performed selectively with heterogeneous catalysts obtained from rhodium and molybdenum carbonyl precursors. Various substrates were reduced in good to high yields and selectivities. Platinum-based catalysts also proved to be efficient. Furthermore, gram-scale experiments were performed and the catalysts could be recycled.

The use of the 2-(4-methylphenylsulfonyl)-ethenyl (tosvinyl, Tsv) group for the protection of the NH group of a series of imides, azinones (including AZT), inosines, and cyclic sulfonamides has been examined. The Tsvprotected derivatives are obtained in excellent yields by conjugate addition to tosylacetylene (ethynyl p-tolyl sulfone). The stereochemistry of the double bond can be controlled at will: with only 1 mol % of Et3N or with catalytic amounts of NaH, the Z stereoisomers are generated almost exclusively, while the E isomers are obtained using a stoichiometric amount of DMAP. Analogous phenylsulfonylvinyl-protected groups (with the besvinyl or Bsv group instead of Tsv) are obtained stereospecifically by reaction with (Z)- or (E)-bis(phenylsulfonyl)ethene. For lactams and oxazolidinones, this last method is much better. The Tsv and Bsv groups are stable in the presence of non-nucleophilic bases and to acids. They can be removed highly effectively via a conjugate addition-elimination mechanism using pyrrolidine or sodium dodecanethiolate as nucleophiles.

There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.