Reduction Of Ketones Research Articles

Mushroom-Mediated Redox Reactions.

The application of biocatalysts in organic synthesis has grown significantly in recent years, and both academia and industry are continuously searching for novel biocatalysts capable of performing challenging chemical reactions. Mushroom is a rich source of ligninolytic and secondary metabolite biosynthetic enzymes, and therefore was consider as promising biocatalysts for organic synthesis. This review focused on the broad utilization potential of the mushroom-based biocatalysts and highlights key advances in mushroom-mediated organic transformations. It mainly includes reduction of ketone and carboxylic acids, hydroxylation of aromatic and aliphatic compounds, epoxidation of olefin, oxidative cleavage of alkene, and other uncommon reactions catalyzed by the whole-cells or purified enzymes of mushroom-origin. Overall, a comprehensive overview of the applications of mushroom as biocatalyst in organic synthesis is provided, which puts this versatile microorganism in the spotlight of further research.

Enhancing the Stability and Activity of Enzymes through Layer-by-Layer Immobilization with Nanocomposite Hydrogel

In this study, a layer-by-layer immobilization strategy was meticulously designed to enhance the stability and activity of enzymes. The approach utilized calcium magnesium carbonate (CaMg(CO3)2) nanoparticles as an immobilization template for abundant binding sites for enzyme attachment but also provide a microenvironment conducive to maintaining enzyme conformation with their unique physicochemical properties. Subsequently, the polymerization of poly(2-hydroxyethyl methacrylate) (pHEMA) to form the nanocomposite hydrogel poly(2-hydroxyethyl methacrylate)-calcium magnesium carbonate (pHEMA-CaMg(CO3)2) introduces a layered architecture, enabling the spatially immobilized enzymes. The pHEMA-CaMg(CO3)2 nanocomposite hydrogel immobilized carbonyl reductase retained over 80% catalytic activity after one month and 81% after 10 cycles of aryl ketone reduction. Similarly, the immobilized lipase within the pHEMA-CaMg(CO3)2 nanocomposite hydrogel exhibited over 80% catalytic activity after one month and demonstrated an impressive 85% activity retention after 10 reuse cycles in glycerol trioctanoate hydrolysis reactions. The FTIR spectra and energy-dispersive X-ray (EDX) spectroscopy mapping showed after multiple repeated uses indicating that the secondary structure of the immobilized enzyme was well preserved, further validating the superiority of our immobilization strategy in safeguarding enzymes integrity and functionality over extended periods and repeated applications.

Preparation, process optimization, and performance study of tea polyphenol-sodium alginate/ethyl cellulose composite microcapsules for green slow-release formaldehyde capture agent

Aiming at the problem of prolonged formaldehyde release from artificial boards, a green slow-release formaldehyde scavenger was proposed in this study. Tea polyphenol microcapsules (TPM) were prepared by ionic gel-solvent evaporation method using sodium alginate/ethyl cellulose as the wall material and tea polyphenol as the core material. Fourier transform infrared spectroscopy (FTIR) analysis showed that the TPM exhibited the same characteristic absorption peaks as those of tea polyphenol, ethyl cellulose and sodium alginate. This indicates that the TPM was successfully prepared and the thermal stability of TPM meets the requirements of the hot pressing process of man-made boards. The optimal process of TPM was as follows: the mass ratio of tea polyphenol to ethyl cellulose was 2.58, the dosage of emulsifier was 1.01 g, and the mass fraction of sodium alginate was 17.23%, the encapsulation rate of TPM was 78.31%, and the average particle size was 18.69 ± 4.66 μm. After 180 min. After 180 min, the aldehyde reduction efficiency was 61.08%. In conclusion, TPM meets the requirements of the production process of wood-based panels and the need for continuous control of formaldehyde emission from wood-based panels.

Microwave-assisted Reduction of Ketones Using Decaborane in Aqueous Solution

The reduction of ketones to secondary alcohols is an essential reaction in organic chemistry, and various reagents are utilized for this purpose. Herein, we have reported the reduction of ketone using decaborane in conventional as well as microwave-assisted methods in aqueous solution. Different types of aromatic ketones containing distinct functional groups were analyzed. We observed that ketones having an electron-withdrawing group showed a faster reaction rate with higher yield as compared to the ketones with electron-donating groups. Additionally, a comparison between microwave- assisted and conventional synthesis was done by evaluating the total reaction time and percentage yield. The results indicate that microwave-assisted syntheses lead to higher yields within very short reaction times.

Stoichiometry Dependence in the Consecutive, Competing Reduction, Halogenation, or Deoxygenation of Aryl Carbonyls.

Six fundamental chemical transformations of aryl carbonyls are achieved by properly adjusting the stoichiometry of the borane-amine and titanium tetrachloride reagent system. This set of reagents acts collectively as a hydride donor, Lewis acid catalyst, and halogen source for the reduction of carbonyls to alcohols, reductive halogenation of carbonyls to halides, deoxygenation of carbonyls to alkanes, dehydroxyhalogenation of alcohols to halides, deoxygenation of alcohols to alkanes, and hydrodehalogenation of halides to alkanes. While the carbonyl reduction is broadly applicable to both aromatic and aliphatic substrates, the remaining reactions are dependent on the stability of the proposed carbocationic intermediates, enabling highly selective reactions at the substrates' benzylic position. This unique selectivity allows benzylic dehalogenation in the presence of aryl and alkyl halides in addition to highly selective dehydroxyhalogenation of alcohols even for tertiary versus secondary aliphatic and secondary versus primary benzylic substrates using only titanium tetrachloride as the chlorinating agent.

Highly efficient Zr-based coordination polymer for catalytic transfer hydrogenation of 5-hydroxymethylfurfural: Tuning acid strength and enhancing stability

In this study, Zr-based coordination polymers were synthesized via solvothermal method for the Meerwein-Ponndorf-Verley reduction of biomass-derived aldehydes and ketones. The morphology and strength of Lewis acid sites could be tuned by using different solvent during catalyst preparation. A 98.5 % yield of 2,5-bis(hydroxymethyl)furan (BHMF) was achieved at 100 °C using Zr-PDC/DMF-DCB, which was synthesized with pyridine-2,6-dicarboxylic acid (PDC) as ligand in a mixed solvent of N, N-dimethylformamide (DMF) and 1,2-dichlorobenzeneisopropanol (DCB) and exhibited moderate Lewis acid sites. Conversely,while Zr-PDC synthesized in alcohols (Zr-PDC/MeOH and Zr-PDC/EtOH) were used as catalysts, etherification products formed instead of BHMF. Further investigation into the role of solvents during catalyst preparation revealed that coordination between Zr sites and DMF increased the electron cloud density of Zr sites, thus weakening Lewis acidity. In addition, the inclusion of hydrophobic DCB resulted in the formation of spherical morphology, which improved resistance to carbon deposition and enhanced anti-agglomeration properties. This work presents a strategy for controlling acid strength and improving catalytic stability of coordination polymers.

Enantiomerically Pure Indazole Bioisosteres of Ifenprodil and Ro 25-6981 as Negative Allosteric Modulators of NMDA Receptors with the GluN2B Subunit.

Administration of negative allosteric modulators of GluN2B subunit-containing NMDA receptors such as Ro 25-6981 (1) and ifenprodil (2) results in neuroprotective effects. In this study, the phenol of 1 and 2 was replaced bioisosterically by an indazole to inhibit glucuronidation. The γ- and β-aminoalcohols 10 and 11 were prepared without installing a protective group at the indazole ring using the ketone 6 as a common intermediate. All four stereoisomeric γ- and β-aminoalcohols 10 and 11 were obtained by diastereoselective reduction of ketones 7 and 9 followed by separation of enantiomers. The analogously structured γ-aminoalcohol (1S,2S)-10c (Ro 25-6981 bioisostere) and β-aminoalcohol (1R,2R)-11c (ifenprodil bioisostere) exhibited high GluN2B affinity (Ki = 50 and 66 nM, respectively) and high to moderate inhibitory activity in two-electrode voltage clamp experiments. The indazole bioisosteres 10 and 11 showed higher metabolic stability than 1. In the presence of uridinyldiphosphate activated glucuronic acid, glucuronidation of 10 and 11 was not observed.

Homobimetallic Ruthenium(II) Complexes Catalysed Selective Transfer Hydrogenation of Aldehydes in Water.

Herein we report chemoselective transfer hydrogenation (TH) of aldehydes in aqueous medium using a series of homobimetallic Ru(II) catalysts. Two homobimetallic complexes (Ru1 and Ru3) and one monometallic complex (Ru2) have been employed in the catalytic reduction of aldehydes. Bimetallic complex [(p-cymene)2(RuCl)2L3] (Ru3) is obtained from the reaction of Schiff base ligand 2,2'-((1E,1'E)-((3,3',5,5'-tetraisopropyl-[1,1'-biphenyl]-4,4'diyl)bis(azaneylylidene))bis(methaneylylidene))bis(4-bromophenol) (H2L3) and characterized by various spectroscopic and analytical techniques. The use of formic acid/formate buffer as the hydride source and a catalyst loading of 0.01 mol% of Ru1 or Ru3 resulted in the conversion of various aldehydes to the corresponding alcohols in good to excellent yield. This method is very efficient for selective reduction of aldehydes in the presence of other reducible functional groups. A loading of 0.0001 mol% of Ru1 catalyst is sufficient to achieve a turnover frequency (TOF) of 5.5× 105 h-1. Furthermore, the catalyst can been recycled and reused for six consecutives cycles without sacrificing the efficiency. A comparison of results obtained between bimetallic and monometallic complexes offers valuable insights into the distinct reactivity patterns of the bimetallic complexes, presumably originating from a cooperative effect. We have explored the mechanistic pathway using DFT methods.

Light‐Responsive Aldehyde‐Reduction Catalysis Through Catalyst Encapsulation

We report a light‐responsive tetrahedral metal–organic capsule that binds a perrhenate catalyst, which is released selectively upon irradiation with 350 nm light, turning on the catalytic reduction of organic carbonyls by hydrosilanes. The catalytic activity can be switched off by heating at 75 °C for 2.5 h, which stimulates capsule reformation and catalyst re‐encapsulation. Multiple on‐off cycles were shown, with a clear relationship between product yield and light irradiation time. Encapsulation thus enables the coupling of light‐responsiveness to catalysis in a manner that might be generalized to other catalysts and capsules.

Light-Responsive Aldehyde-Reduction Catalysis Through Catalyst Encapsulation.

We report a light-responsive tetrahedral metal-organic capsule that binds a perrhenate catalyst, which is released selectively upon irradiation with 350 nm light, turning on the catalytic reduction of organic carbonyls by hydrosilanes. The catalytic activity can be switched off by heating at 75 °C for 2.5 h, which stimulates capsule reformation and catalyst re-encapsulation. Multiple on-off cycles were shown, with a clear relationship between product yield and light irradiation time. Encapsulation thus enables the coupling of light-responsiveness to catalysis in a manner that might be generalized to other catalysts and capsules.

NAD(P)-Dependent Glucose Dehydrogenases: Underestimated Multifunctional Biocatalysts.

The last decade has witnessed tremendous progress in the field of biocatalysis. One of the most frequently utilized enzymes in diverse biocatalytic applications is NAD(P)-dependent glucose dehydrogenases (GDHs). Traditionally, these enzymes are employed for their role in regenerating NAD(P)H in various enzymatic reactions utilizing glucose. However, recent studies have expanded the scope of GDHs beyond cofactor regeneration, highlighting their potential as biocatalysts in diverse chemical transformations. GDHs have demonstrated versatility in catalyzing key reactions in the synthesis of various drug molecules and intermediates, including ketone reduction to produce alcohols, imine reduction of C=N bonds to yield amines, reduction of aldehydes to alcohols, and dehydrogenation of cyclohexanol derivatives. This review highlights recent advancements in elucidating the multifunctional roles of NAD(P)-dependent glucose dehydrogenases (GDHs) in biocatalysis, with an emphasis on their growing applications and significant potential in small molecule synthesis.

Electrochemical Hydrodimerization of Lignocellulose-Derived Carbonyls in Aqueous Electrolytes for Biobased Polymer and Long-chained Synfuel Production: A Review.

The transformation from fossil resources, crude oil and natural gas to biomass-derived feedstocks is an urgent and major challenge for the chemical industry. The valorization of lignocellulose as renewable resource is a promising pathway offering access to a wide range of platform chemicals, such as vanillin, furfural and 5-HMF. The subsequent conversion of such platform chemicals is one crucial step in the value-added chain. The electrochemical hydrodimerization (EHD) is a sustainable tool for C-C coupling of these chemicals to their corresponding hydrodimers hydrovanilloin, hydrofuroin and 5,5'-bis(hydroxymethyl)hydrofuroin (BHH). This review covers the current state of art concerning the mechanism of the electrochemical reduction of biobased aldehydes and studies targeting the electrochemical production of these hydrodimers in aqueous media. Moreover, the subsequent conversion of these hydrodimers to valuable additives, polymers and long carbon chain synfuels will be summarized offering a broad scope for their application in the chemical industry.

Micellar Transfer Hydrogenation Catalysis in Water with Monocarbonyl Ruthenium(II)-poly(vinylphosphonate)-Containing Polymers: Achieving Reduction of Biomass-Derived Aldehydes

Micellar Transfer Hydrogenation Catalysis in Water with Monocarbonyl Ruthenium(II)-poly(vinylphosphonate)-Containing Polymers: Achieving Reduction of Biomass-Derived Aldehydes

Switching the Stereopreference of TeSADH: Enabling Anti‐Prelog Asymmetric Reduction of Aryl‐Ring‐Containing Ketones

AbstractThe biocatalytic asymmetric reduction of prochiral ketones offers a promising approach for producing optically active secondary alcohols. Alcohol dehydrogenases (ADHs) are enzymes that facilitate the reversible conversion of prochiral ketones into their corresponding optically active secondary alcohols, and thus are pivotal for this process. Most ADHs adhere to Prelog's rule in determining the stereopreference for the asymmetric reduction of prochiral ketones. This study focuses on the ΔP84/A85G mutation of TeSADH, demonstrating its capability to reduce aryl‐ring‐containing ketones to their corresponding alcohols in anti‐Prelog mode with high stereoselectivities. The study also highlights the crucial role of P84 in switching the stereopreference of TeSADH in the asymmetric reduction of aryl‐ring‐containing ketones. Furthermore, this mutant exhibits a broad substrate scope, including substrates accepted by the previously reported W110 mutants of TeSADH with opposite stereopreference. The ability to create mutants of the same enzyme with opposite stereopreferences presents intriguing opportunities for fascinating transformations, such as bienzymatic racemization, which can be utilized in dynamic kinetic resolution, and stereoinversion using two enantiocomplementary mutants of the same enzyme.

Overview of Baker's Yeast as a Biocatalyst

Biocatalysis is an approach to green chemistry. A crucial step in the synthesis of or-ganic compounds is the reduction of aldehydes and ketones to secondary alcohols. The use of a biocatalyst, such as enzymes or entire cells, has not affected this process.. It offers great selectiv-ity, high specificity, and an environmentally friendly approach to synthesis. Dried baker's yeast mediates the conversion of optically active alcohols from aromatic aldehydes and ketones. This work highlights applications of Baker's yeast in synthesizing pharmaceutical intermediates and chiral building blocks, demonstrating its practical relevance. Sustainable technology is based on the ideas and measurements of sustainable development and green for good enantioselectivity across several organic solvents.

A Concise Synthesis of (2R,6R)-Hydroxynorketamine.

A concise synthesis of (2R,6R)-hydroxynorketamine was accomplished in eight steps, starting from commercially available materials. This synthesis features a cerium chloride-enhanced Stork-Danheiser reaction, an asymmetric reduction of ketone by the Corey-Bakshi-Shibata reaction, a signature Overman rearrangement, and a facial selective dihydroxylation of an electronically deficient olefin by RuCl3/NaIO4. The overall yield is 7.3% with 94.5% ee.

Introduction of a new cobalt-containing Lewis acidic ionic liquid catalyst for the reduction of nitroaromatic compounds and aldehydes and one-pot reductive acetylation of arylaldehydes

Introduction of a new cobalt-containing Lewis acidic ionic liquid catalyst for the reduction of nitroaromatic compounds and aldehydes and one-pot reductive acetylation of arylaldehydes

Redox Biocatalysis in Lidocaine-based Hydrophobic Deep Eutectic Solvents: Non-conventional Media Outperform Aqueous Conditions.

Redox biocatalysis is an important pillar of the chemical industry. Yet, the enzymes' nature restricts most reactions to aqueous conditions, where the limited substrate solubility leads to unsustainable diluted biotranformations. Non-aqueous media represent a strategic solution to conduct intensified biocatalytic routes. Deep eutectic solvents (DESs) are designable solvents that can be customized to meet specific application needs. Within the large design space of combining DES components (and ratios), hydrophobic DESs hold the potential to be both enzyme-compatible - keeping the enzymes' hydration -, and solubilizers for hydrophobic reactants. We explored two hydrophobic DESs, lidocaine/oleic acid, and lidocaine/decanoic acid, as reaction media for carbonyl reduction catalyzed by horse liver alcohol dehydrogenase, focusing on the effect of water contents and on maximizing substrate loadings. Enzymes remained highly active and stable in the DESs with 20 wt.% buffer, whereas the reaction performance in DESs outperformed the pure buffer system with hydrophobic substrates (e.g., cinnamaldehyde to form the industrially relevant cinnamyl alcohol), with a 2-fold higher specific activity. Notably, the cinnamaldehyde reduction was for the first time performed at 800 mM (~100 g[[EQUATION]]L-1) with full conversion, which opens up new avenues to industrial applications of hydrophobic DESs for enzyme catalysis.

A mild and chemoselective photoredox-catalyzed reduction of aromatic ketones

A mild, chemoselective reduction of aromatic ketones was discovered and investigated. The combination of photoredox and Lewis acid catalysis with an organic hydrogen source reduced aromatic ketones in good to high yield. Optimization found 2-phenylbenzothiazoline to be a sufficiently strong source of hydrogen in combination with an iridium photosensitizer and lanthanum triflate. Effective photomediated reduction of some substrates was also observed in the absence of photocatalyst and Lewis acid or with photocatalyst only. While yields were typically higher under catalytic conditions, some acid-sensitive substrates were more effectively reduced in the absence of Lewis acid. The reaction was generally high yielding, and chemoselective, while tolerant of complex and functionally rich molecules.

Bioreduction of aromatic ketones catalyzed by oak fruits (Quercus Ilex L ) fruit grown in north Algeria

The present work primarily aims to investigate and establish a method for the bioreduction of aromatic ketones to produce corresponding alcohols. This process is crucial for the production of various industrially important chemicals, including pharmaceuticals, agrochemicals, and natural products, and supports the principles of green chemistry. Additionally, this study seeks to valorize the vegetation cover in southern Algeria as a source of biochemical catalysts. Our research focused on the bioreduction of several acetophenone derivatives using the fruits of Oak (Quercus ilex L.) which is cultivated in northern Algeria. The findings indicate that these plant tissues can effectively reduce acetophenone derivatives. Specifically, a chemical yield of approximately 90% was achieved for acetophenone, while yields ranged from 60% to 75% for 4'-haloacetophenones (where X = F, Cl, and Br) and 4'-nitroacetophenone. These results demonstrate that (Quercus ilex L).fruits from northern Algeria can serve as effective biocatalysts in the reduction of aromatic ketones to their corresponding alcohols. This approach not only supports the sustainable production of pharmaceuticals but also provides significant health, environmental, economic, and medical benefits.