Hydrolysis Of Nitriles Research Articles

A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant

A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant has been developed. Using this procedure, a variety of nitriles could be smoothly transformed into the desired primary amides in good to excellent yields. The mild reaction conditions and the flowing reaction system greatly improved the safety and make the reaction easy to scale up.

In vitro metabolism of the synthetic cannabinoids CUMYL-PINACA, 5F-CUMYL-PINACA, CUMYL-4CN-BINACA, 5F-CUMYL-P7AICA and CUMYL-4CN-B7AICA.

Synthetic cannabinoid consumption trends underlie fast changes and provide several challenges to clinical and forensic toxicologists. Due to their extensive metabolism, parent compounds are hardly detectable in urine. Therefore, knowledge of the metabolism of synthetic cannabinoids is essential to allow their detection in biological matrices. The aim of the present study was the elucidation of the metabolism of CUMYL-PINACA, 5F-CUMYL-PINACA, CUMYL-4CN-BINACA, 5F-CUMYL-P7AICA, and CUMYL-4CN-B7AICA with a focus on the analytical and interpretational differentiation of the compounds. Microsomal assay mixtures containing co-substrates, 10μg/mL substrate and 1mg/mL pooled human liver microsomes were incubated for 1hour at 37°C. Investigation of the metabolites was performed on a Thermo Fischer Ultimate 3000 UHPLC system coupled to a Sciex 6600 QTOF System. Hydroxylation was observed to be a major biotransformation step for all 5 cumyl-derivatives, followed by dihydroxylation. For CUMYL-PINACA, a major metabolic pathway was hydroxylation at the pentyl moiety, followed by a second hydroxylation at that pentyl moiety or oxidation to ketone. A major metabolic pathway for the compounds containing a nitrile function was nitrile hydrolysis followed by carboxylation and further hydroxylation. For the fluorinated compounds, oxidative defluorination and carboxylation were abundant metabolic steps. Some of the metabolic transformations lead to structurally identical metabolites, which should not be used as marker for the intake of a particular parent compound. In addition, several constitutional isomers containing either an indazole or azaindole core structure were detected, which should be differentiated by retention time rather than by their mass spectra alone.

Highly chemoselective and efficient production of 2,6-difluorobenzamide using Rhodococcus ruber CGMCC3090 resting cells

Chemoselective biocatalytic hydrolysis of nitriles is a valuable alternative to chemical hydrolysis that operates under harsh conditions. 2,6-Difluorobenzamide (DFBAM) is an essential intermediate derived from synthesis of benzoyl urea insecticide from 2,6-difluorobenzonitrile (DFBN). High yield of DFBAM was achieved, and the method using resting cells of Rhodococcus ruber CGMCC3090 exhibited excellent product specificity. The reaction parameters for DFBAM biosynthesis were also investigated. The resting cells effectively converted DFBN at high concentrations of up to 3.5molL-1 without forming acids or other by-products. Therefore, biological production of DFBAM features high yield, chemoselectivity, low cost, and environment friendliness and is more suitable to the industry than chemical synthesis techniques.

Erratum to: Enhancing the catalytic potential of nitrilase from Pseudomonas putida for stereoselective nitrile hydrolysis.

(R)-mandelic acid was produced from racemic mandelonitrile using free and immobilized cells of Pseudomonas putida MTCC 5110 harbouring a stereoselective nitrilase. In addition to the optimization of culture conditions and medium components, an inducer feeding approach is suggested to achieve enhanced enzyme production and therefore higher degree of conversion of mandelonitrile. The relationship between cell growth periodicity and enzyme accumulation was also studied, and the addition of the inducer was delayed by 6 h to achieve maximum nitrilase activity. The nitrilase expression was also authenticated by the sodium dodecyl phosphate-polyacrylamide gel electrophoresis analysis. P. putida MTCC 5110 cells were further immobilized in calcium alginate, and the immobilized biocatalyst preparation was used for the enantioselective hydrolysis of mandelonitrile. The immobilized system was characterized based on the Thiele modulus (ϕ). Efficient biocatalyst recycling was achieved as a result of immobilization with immobilized cells exhibiting 88% conversion even after 20 batch recycles. Finally, a fed batch reaction was set up on a preparative scale to produce 1.95 g of (R)-(-)-mandelic acid with an enantiomeric excess of 98.8%.

Controlled photocatalytic hydrolysis of nitriles to amides by mesoporous MnO 2 nanoparticles fabricated by mixed surfactant mediated approach

Abstract The solid-phase MnO 2 nanoparticles fabricated by surfactant template method were exploited as the photocatalyst for the effective one-step synthesis of amides. Cationic or anionic surfactants and their combinations were used as porous templates to obtain the mesoporous MnO 2 nanoparticles with variable pore volume (0.23–1.95 cm 3 /g). The morphological and structural observation of the material confirms the uniform facet structure (37.68 nm) of MnO 2 nanoparticles. The surface elemental state was confirmed by XPS analysis confirming Mn 2p 3/2 (642.5 eV) and Mn2p 1/2 (654.7 eV) spin states, that are common for the tetravalent Mn ions. Presence of surfactant as stabilizer was also witnessed with a strong peak of C 1s (283–286 eV). The textural parameters obtained from XRD and Raman analysis depicted the β-phase and rutile type framework of MnO 2 . The selective conversion of nitriles to amides was studied without any acid by products under visible light irradiation in the basic/neutral medium. Amides were obtained from various substrates (nitriles) with excellent yields (70–90%).

Hydrolysis of nitriles by soil bacteria: variation with soil origin.

The aim of this study was to explore bacterial soil diversity for nitrile biocatalysts, in particular, those for hydrolysis of β-substituted nitriles, to the corresponding carboxamides and acids that may be incorporated into peptidomimetics. To achieve this, we needed to compare the efficiency of isolation methods and determine the influence of land use and geographical origin of the soil sample. Nitrile-utilizing bacteria were isolated from various soil environments across a 1000km long transect of South Africa, including agricultural soil, a gold mine tailing dam and uncultivated soil. The substrate profile of these isolates was determined through element-limited growth studies on seven different aliphatic or aromatic nitriles. A subset of these organisms expressing broad substrate ranges was evaluated for their ability to hydrolyse β-substituted nitriles (3-amino-3-phenylpropionitrile and 3-hydroxy-4-phenoxybutyronitrile) and the active organisms were found to be Rhodococcus erythropolis from uncultivated soil and Rhodococcus rhodochrous from agricultural soils. The capacity for hydrolysis of β-substituted nitriles appears to reside almost exclusively in Rhodococci. Land use has a much greater effect on the biocatalysis substrate profile than geographical location. Enzymes are typically substrate specific in their catalytic reactions, and this means that a wide diversity of enzymes is required to provide a comprehensive biocatalysis toolbox. This paper shows that the microbial diversity of nitrile hydrolysis activity can be targeted according to land utilization. Nitrile biocatalysis is a green chemical method for the enzymatic production of amides and carboxylic acids that has industrial applications, such as in the synthesis of acrylamide and nicotinamide. The biocatalysts discovered in this study may be applied to the synthesis of peptidomimetics which are an important class of therapeutic compounds.

Metal-Assisted Oxo Atom Addition to an Fe(III) Thiolate.

Cysteinate oxygenation is intimately tied to the function of both cysteine dioxygenases (CDOs) and nitrile hydratases (NHases), and yet the mechanisms by which sulfurs are oxidized by these enzymes are unknown, in part because intermediates have yet to be observed. Herein, we report a five-coordinate bis-thiolate ligated Fe(III) complex, [FeIII(S2Me2N3(Pr,Pr))]+ (2), that reacts with oxo atom donors (PhIO, IBX-ester, and H2O2) to afford a rare example of a singly oxygenated sulfenate, [FeIII(η2-SMe2O)(SMe2)N3(Pr,Pr)]+ (5), resembling both a proposed intermediate in the CDO catalytic cycle and the essential NHase Fe-S(O)Cys114 proposed to be intimately involved in nitrile hydrolysis. Comparison of the reactivity of 2 with that of a more electron-rich, crystallographically characterized derivative, [FeIIIS2Me2NMeN2amide(Pr,Pr)]- (8), shows that oxo atom donor reactivity correlates with the metal ion's ability to bind exogenous ligands. Density functional theory calculations suggest that the mechanism of S-oxygenation does not proceed via direct attack at the thiolate sulfurs; the average spin-density on the thiolate sulfurs is approximately the same for 2 and 8, and Mulliken charges on the sulfurs of 8 are roughly twice those of 2, implying that 8 should be more susceptible to sulfur oxidation. Carboxamide-ligated 8 is shown to be unreactive towards oxo atom donors, in contrast to imine-ligated 2. Azide (N3-) is shown to inhibit sulfur oxidation with 2, and a green intermediate is observed, which then slowly converts to sulfenate-ligated 5. This suggests that the mechanism of sulfur oxidation involves initial coordination of the oxo atom donor to the metal ion. Whether the green intermediate is an oxo atom donor adduct, Fe-O═I-Ph, or an Fe(V)═O remains to be determined.

Biofilms of nitrile-hydrolyzing bacteria: Dynamics of growth, resistance to toxic substances, and biotechnological potential

Monospecies and mixed bacterial biofilms of Rhodococcus ruber gt1, Pseudomonas fluorescens C2, Alcaligenes faecalis 2, and Rh. erythropolis 11-2 were obtained during growth in presence of the carriers. The transformation of aliphatic and aromatic nitriles by the biofilms of nitrile-hydrolyzing bacteria, as well as the growth dynamics of Rh. ruber gt1 and P. fluorescens C2 biofilms and their resistance to toxic substrates and products of nitrile hydrolysis, were studied. It was shown that the P. fluorescens C2 biofilm mass and total ATP content reached the maxima after 1 day of growth, whereas Rh. ruber gt1 reached them after 3–4 days of cultivation. The biofilms of Rh. ruber gt1 and P. fluorescens C2 were more resistant to the effects of high concentrations of acrylamide and acrylonitrile and had a greater adaptive capacity than planktonic cells.

Pressure Regulations on the Surface Properties of CeO2 Nanorods and Their Catalytic Activity for CO Oxidation and Nitrile Hydrolysis Reactions.

Surface properties of nanoscale CeO2 catalysts in terms of the surface Ce(3+) fraction and concentration of oxygen vacancy can affect their catalytic performance significantly. Continual adjustment on surface properties of CeO2 with the morphological preservation has not been realized by synthetic methods. The revisited studies show that surface properties of CeO2 nanorods can be effectively regulated by synthetic pressures while the rodlike morphology is well-preserved. Such phenomena are ascribed to the contact possibility between Ce(3+) species and dissolved O2, which is balanced by the rapidly increased and gradually saturated dissolution/recrystallization rate of Ce(OH)3 and linearly increased concentration of dissolved O2 with the increase of total air pressure or partial pressure of O2. Surface-property-dependent catalytic activity of CeO2 nanorods synthesized under various pressures was also demonstrated in two benchmark reactions-catalytic oxidation of CO and hydrolysis of nitrile. Such a finding of the pressure regulation on the reducible metal oxides provides an effective approach to rationally design novel catalysts for specific reactions, where ceria are supports, promoters, or actives.

Profiles of Glucosinolates, Their Hydrolysis Products, and Quinone Reductase Inducing Activity from 39 Arugula (Eruca sativa Mill.) Accessions.

Glucosinolates, their hydrolysis product concentrations, and the quinone reductase (QR) inducing activity of extracts of leaf tissue were assayed from 39 arugula (Eruca sativa Mill.) accessions. Arugula accessions from Mediterranean countries (n = 16; Egypt, Greece, Italy, Libya, Spain, and Turkey) and Northern Europe (n = 2; Poland and United Kingdom) were higher in glucosinolates and their hydrolysis products, especially glucoraphanin and sulforaphane, compared to those from Asia (n = 13; China, India, and Pakistan) and Middle East Asia (n = 8; Afghanistan, Iran, and Israel). The QR inducing activity was also the highest in Mediterranean and Northern European arugula accessions, possibly due to a significant positive correlation between sulforaphane and QR inducing activity (r = 0.54). No nitrile hydrolysis products were found, suggesting very low or no epithiospecifier protein activity from these arugula accessions. Broad sense heritability (H(2)) was estimated to be 0.91-0.98 for glucoinolates, 0.55-0.83 for their hydrolysis products, and 0.90 for QR inducing activity.

Developing a Biocascade Process: Concurrent Ketone Reduction-Nitrile Hydrolysis of 2-Oxocycloalkanecarbonitriles.

A stereoselective bioreduction of 2-oxocycloalkanecarbonitriles was concurrently coupled to a whole cell-catalyzed nitrile hydrolysis in one-pot. The first step, mediated by ketoreductases, involved a dynamic reductive kinetic resolution, which led to 2-hydroxycycloalkanenitriles in very high enantio- and diastereomeric ratios. Then, the simultaneous exposure to nitrile hydratase and amidase from whole cells of Rhodococcus rhodochrous provided the corresponding 2-hydroxycycloalkanecarboxylic acids with excellent overall yield and optical purity for the all-enzymatic cascade.

ChemInform Abstract: Palladium‐Catalyzed Synthesis of Aryl Amides Through Silanoate‐Mediated Hydrolysis of Nitriles.

AbstractThe starting amide salts are prepared by reaction of appropriate nitriles with Tms—OK according to a known procedure.

Highlights of the Recent U.S. Patent Literature: Focus on Biocatalysis

Biocatalysis is playing an increasingly important role in organic synthesis and for industrial manufacture of fine chemicals and pharmaceutical APIs. This review highlights patents and patent applications describing new applications of enzymes for organic synthesis—cyclopropanation, Diels–Alder reactions, reductive amination, and nitrile hydrolysis. These enzymatic processes are still early in development, but industrial application is likely just waiting for the right opportunity.

Biocatalytic Desymmetrization of Dinitriles in Organic Synthesis

In comparison with the chemical hydration and hydrolysis of nitriles, which usually involves harsh reaction condi- tions and low selectivity, biocatalytic desymmetrizations of prochiral or meso nitriles are highly efficient, highly enantioselec- tive and environmentally benign. Therefore, biocatalysis and biotransformation has offered an attractive and unique protocol for the enantioselective synthesis of polyfunctionalized organic compounds that are not readily obtainable by other methods. This review summarizes the biocatalytic desymmetrization of prochiral nitriles including glutaronitriles, malonitriles and meso cyclic dinitriles during the past two decades. Keywords desymmetrization; biotransformations; dinitriles 生物转化是利用生物催化体系(如各种细胞和酶等)

Palladium-Catalyzed Synthesis of Aryl Amides through Silanoate-Mediated Hydrolysis of Nitriles

A procedure for the formation of aryl amides through the palladium-catalyzed coupling of nitriles and aryl bromides, via the formation of intermediary silanoate derived imidate species is reported. Optimization was undertaken and examples of the process are described that furnish the products in up to 86% isolated yield.

Cyanide hydratases and cyanide dihydratases: emerging tools in the biodegradation and biodetection of cyanide.

The purpose of this study is to summarize the current knowledge of the enzymes which are involved in the hydrolysis of cyanide, i.e., cyanide hydratases (CHTs; EC 4.2.1.66) and cyanide dihydratases (CynD; EC 3.5.5.1). CHTs are probably exclusively produced by filamentous fungi and widely occur in these organisms; in contrast, CynDs were only found in a few bacterial genera. CHTs differ from CynDs in their reaction products (formamide vs. formic acid and ammonia, respectively). Several CHTs were also found to transform nitriles but with lower relative activities compared to HCN. Mutants of CynDs and CHTs were constructed to study the structure-activity relationships in these enzymes or to improve their catalytic properties. The effect of the C-terminal part of the protein on the enzyme activity was determined by constructing the corresponding deletion mutants. CynDs are less active at alkaline pH than CHTs. To improve its bioremediation potential, CynD from Bacillus pumilus was engineered by directed evolution combined with site-directed mutagenesis, and its operation at pH 10 was thus enabled. Some of the enzymes have been tested for their potential to eliminate cyanide from cyanide-containing wastewaters. CynDs were also used to construct cyanide biosensors.

EQCM and XPS investigations on the redox switching of conducting poly(o-aminophenol) films electrosynthesized onto Pt substrates

The redox behaviour of conducting poly(o-aminophenol) films (PoAP), potentiodynamically electrosynthesized onto Pt substrates, was studied by means of in situ Electrochemical Quartz Crystal Microbalance (EQCM), varying the composition, concentration and pH of the acidic supporting electrolyte. PoAP films at different oxidation stages were also characterized by ex situ X-ray Photoelectron Spectroscopy (XPS), stopping the anodic scan at +0.1V (semi-oxidized PoAP) and +0.5V vs Ag/AgCl (oxidized PoAP). The results were interpreted by comparison with previous investigations carried out on the reduced PoAP.Polymer oxidation proceeds through the deprotonation of aminic site susceptible then to oxidation. The incorporation of perchlorate ions occurs mostly at the beginning of the anodic scan till the peak potential is reached. At this stage of the oxidation positively charged nitrogens, polaron type, are present which then recombine each other to give bipolaron and, upon deprotonation, neutral immines. The overall PoAP redox oxidation is a reversible two electrons process complicated by chemical deprotonation steps before and after the oxidation itself. On the reverse scan immines require protonation in order to be reduced. A diffusional type limitation on the cathodic process was demonstrated and attributed to counter ions diffusion through the polymer accompanying its protonation.The XPS investigation allowed to unambiguously prove the presence of water inside the film, already suggested by the authors for the reduced PoAP by heating experiments in ultra-high vacuum conditions. Rinsing the polymer with acetonitrile before the XPS analysis, the relevant detailed C1s, N1s and O1s regions evidenced the presence of ammonium acetate coming from nitrile hydrolysis. A higher amount of water was evidenced in the oxidized states with respect to the reduced form. The exchanged molar mass calculated by EQCM revealed, indeed, solvent entrance in the last part of the oxidation. Accordingly, the Binding Energies characteristic of neutral nitrogen functionalities suggested that polymer chains are more distant in the oxidized state, preventing the incoming of hydrogen bonds.

Expression and Characterization of a Novel Nitrilase from Hyperthermophilic Bacterium Thermotoga maritima MSB8.

The present study describes the gene cloning, overexpression and characterization of a novel nitrilase from hyperthermophilic bacterium Thermotoga maritima MSB8. The nitrilase gene consisted of 804 base pairs, encoding a protein of 268 amino acid residues with a molecular mass of 30.07 kDa after SDS-PAGE analysis. The optimal temperature and pH of the purified enzyme were 45°C and 7.5, respectively. The enzyme demonstrated good temperature tolerance, with 40% residual activity after 60 min of heat treatment at 75°C. The kinetic constants Vmax and Km of this nitrilase toward 3-cyanopyridine were 3.12 μmol/min/mg and 7.63 mM, respectively. Furthermore, this novel nitrilase exhibited a broad spectrum toward the hydrolysis of the aliphatic nitriles among the tested substrates, and particularly was specific to aliphatic dinitriles like succinonitrile, which was distinguished from most nitrilases ever reported. The catalytic efficiency kcat/Km was 0.44 /mM/s toward succinonitrile. This distinct characteristic might enable this nitrilase to be a potential candidate for industrial applications for biosynthesis of carboxylic acid.

Cloning, purification and evaluation of the enzymatic properties of a novel arylacetonitrilase from Luminiphilus syltensis NOR5-1B: a potential biocatalyst for the synthesis of mandelic acid and its derivatives.

To examine nitrilase-mediated hydrolysis of nitriles to produce optically pure α-hydroxycarboxylic acids. A novel nitrilase, GPnor51, from Luminiphilus syltensis NOR5-1B was discovered by genomic data mining. It could hydrolyze racemic o-chloromandelonitrile to (R)-o-chloromandelic acid with high enantioselectivity (ee 98.2 %). GPnor51 was overexpressed in Escherichia coli BL21 (DE3), purified, and its catalytic properties studied. GPnor51 had a broad substrate acceptance toward various nitriles with structure diversity. It was an arylacetonitrilase that uses arylacetonitriles as optimal substrates. The V max and K m of GPnor51 towards o-chloromandelonitrile were 1.9 μmol min(-1) mg(-1) protein and 0.38 mM, respectively. GPnor51 also demonstrated high enantioselectivity toward mandelonitrile and other substituted mandelonitrile. This enzyme has a great potential for commercial production of optically pure (R)-mandelic acid and its derivatives.

Isolation and identification of a nitrile hydrolyzing bacterium and simultaneous utilization of aromatic and aliphatic nitriles

Rhodococcus sp. MTB5, a bacterial strain capable of utilizing benzonitrile as the sole source of carbon and nitrogen was isolated from a nitrile-contaminated agricultural soil sample by selective enrichment culture technique. This bacterial strain is capable of utilizing both aliphatic and aromatic nitriles. The production of ammonia was noticed during the growth of this strain in the medium supplemented with benzonitrile. The enzyme assay and GC studies revealed that benzonitrile degradation by Rhodococcus sp. MTB5 follows a NHase/amidase pathway involving benzamide and benzoic acid as metabolic intermediates. The resting cells grown on benzonitrile showed NHase and amidase activities of 0.155 and 0.261 units, respectively. The strain utilized 30 mM benzonitrile completely and could tolerate and grow in benzonitrile at concentration up to 60 mM. The cells grown on glucose and ammonium nitrate did not show the above enzymatic activities indicating the inducible nature of these enzymes. In addition to benzonitrile, the isolate was also able to utilize indole-3-acetonitrile and aliphatic nitriles, namely, propionitrile, butyronitrile and valeronitrile. Furthermore, the bacterium simultaneously utilizes different combinations of aromatic and aliphatic nitriles. These novel features make the bacterium a suitable candidate for the in-situ application of sites contaminated with both aliphatic and aromatic nitriles.