Reaction Of Glyoxylic Acid Research Articles

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates.

A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid, sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural products.

A spectrophotometric method for the determination of tryptophan following oxidation by the addition of sodium hypochlorite pentahydrate.

Tryptophan (Trp) is an essential amino acid that functions in various biological processes and human daily health. As the significant functions of Trp become more apparent, its measurement is becoming increasingly important in various situations. Herein, we improved the Trp color reaction based on the Hopkins-Cole reaction and established a simple colorimetric method for Trp determination using several different reagents, including sodium hypochlorite pentahydrate and monosodium glutamate. The detection method can be performed using safe materials, rather than conventional toxic substances, and induces a crimson color change with an absorption peak at 525 nm, enabling the quantification of Trp by simple spectrophotometry in just 10 min. This assay exhibited a linear detection range from 10 to 100 mg/L (R2 = 0.9996). The average recoveries in the spiked cerebrospinal fluid ranged from 90.5% to 104.3%, with a relative standard deviation of 0.27% (n = 3, 29.40 mg/L Trp) to 1.19% (n = 3, 72.90 mg/L Trp). This novel spectrophotometric method may enable many researchers and laboratory technicians to detect Trp in various sample solutions without expensive analytical instruments or complicated operations.

The influence of bioactive glyoxylate bearing Schiff base on antifungal and antioxidant activities to chitosan quaternary ammonium salts

In this study, to investigate the influence of glyoxylate bearing Schiff base on bioactivity to chitosan quaternary ammonium salts, different chitosan derivatives were synthesized by ion exchange of glyoxylate bearing Schiff base with chitosan quaternary ammonium salts (TMCI and HACC). For this purpose, glyoxylate was prepared by Schiff base reaction of glyoxylic acid and amino heterocycles and it was further ionization to substitute iodide ions and chloride ions. After structural characterization by FTIR and 1H NMR, the antifungal and antioxidant activities were measured. Results indicated that glyoxylate bearing Schiff base could improve the bioactivity of TMCI and HACC obviously. Specifically, anionic TMCI with Schiff base of amino pyridines possessed best antioxidant activity >92.40% at 1.6 mg/mL against DPPH radicals. Meanwhile, they showed antifungal activity >84.88% at 1.0 mg/mL against G. cingulate. Furthermore, the cytotoxicity was evaluated, and all samples showed good cell viability >80.14% at 1000 μg/mL.

Cross Photoreaction of Glyoxylic and Pyruvic Acids in Model Aqueous Aerosol.

Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps. During irradiation, PA and GA are excited and initiate proton-coupled electron transfer or hydrogen abstraction and α-cleavage reactions, respectively. The time series of photoproducts is studied by ion chromatography (IC) with conductivity and electrospray ionization (ESI) mass spectrometry (MS) detection, direct ESI-MS analysis in the negative ion mode, and nuclear magnetic resonance spectroscopy (NMR). The use of one-dimensional (1H and 13C NMR) and two-dimensional NMR techniques includes gradient correlation spectroscopy (gCOSY) and heteronuclear single quantum correlation (HSQC). The aging of photoproducts in the dark is monitored by UV-visible spectroscopy. The periodicity in the time domain of the optical properties is explained in terms of chromophores that undergo alternating thermochromism and photobleaching between nighttime and daytime cycles, respectively. A reaction mechanism for the cross reaction of GA and PA explaining the generation of trimers with general formulas C5H8O5 (148 Da), C6H10O5 (162 Da), and C5H8O6 (164 Da) is provided based on all experimental observations.

Clustering mechanism of oxocarboxylic acids involving hydration reaction: Implications for the atmospheric models.

The formation of atmospheric aerosol particles from condensable gases is a dominant source of particulate matter in the boundary layer, but the mechanism is still ambiguous. During the clustering process, precursors with different reactivities can induce various chemical reactions in addition to the formation of hydrogen bonds. However, the clustering mechanism involving chemical reactions is rarely considered in most of the nucleation process models. Oxocarboxylic acids are common compositions of secondary organic aerosol, but the role of oxocarboxylic acids in secondary organic aerosol formation is still not fully understood. In this paper, glyoxylic acid, the simplest and the most abundant atmospheric oxocarboxylic acid, has been selected as a representative example of oxocarboxylic acids in order to study the clustering mechanism involving hydration reactions using density functional theory combined with the Atmospheric Clusters Dynamic Code. The hydration reaction of glyoxylic acid can occur either in the gas phase or during the clustering process. Under atmospheric conditions, the total conversion ratio of glyoxylic acid to its hydration reaction product (2,2-dihydroxyacetic acid) in both gas phase and clusters can be up to 85%, and the product can further participate in the clustering process. The differences in cluster structures and properties induced by the hydration reaction lead to significant differences in cluster formation rates and pathways at relatively low temperatures.

Transport and Reactants Concentration Effects in Electroless Deposition of Copper

Electroless deposition offers the capability of metalizing non-conductive substrates and electrically isolated features. This is achieved by reducing the deposited ion using a chemical reducing agent rather than by externally provided current. However, despite its technological importance, the electroless process is still poorly characterized with little understanding of the factors that control the deposition rates. In particular, the significant effect of transport on the electroless process has received very little attention. The underlying model for electroless plating is the mixed potential theory, proposed by Wagner and Traud1, which states that in order to assure charge balance, the electroless process must proceed at the rate and potential where the two separate redox reactions exhibit the same and opposite currents. While the basic stipulation of the mixed potential theory is always valid, its application to electroless systems has exhibited inconsistent results. This failure is most likely due to the interactions between the two redox chemistries, and effects due to the freshly deposited substrate in the complete system, which are not encountered in the separate half-cell processes. This leads to discrepancies between the polarization curves measured for the individual redox reactions and the prevailing conditions in the combined system, which are not accessible to direct electrochemical measurements. As detailed below, we address this deficiency using two different approaches. We apply our analysis to a system where the mixed potential theory fails to predict the observed rates.2The system consists of copper sulfate, ethylenediaminetetraacetic acid as a complexing agent, glyoxylic acid as a reducing agent, and sodium hydroxide which is used to adjust the pH to 12.8. The first approach is based on polarizing the complete electroless system, allowing external current to flow simultaneously with the electroless process. From the difference between the measured amount of deposited copper and the total external current, the glyoxylic acid reaction rate can be determined. Translating the copper and glyoxylic acid reaction rates to currents, polarization curves can be generated for the two reactions (copper deposition and glyoxylic acid oxidation) as they occur in the full electroless system. As shown in Fig. 1, these rates are significantly different in the combined system as compared to the separately measured polarization curves. In particular, the copper deposition rate is significantly enhanced in the full electroless system as indicated in Fig. 1. A second approach taken to analyze and model the electroless system is based on formulating rate expressions, in terms of reaction rate power law, for each of the two redox reactions taking place simultaneously in the electroless process. The rate expressions incorporate the reactants and products concentrations raised to arbitrary powers, and potential-dependent Arrhenius type rate constants. As both reactions occur in electroless plating on the same surface in the absence of external current, their rates must be equal. From this equality, separate expressions for current density and mixed potential are developed. The rate constants and powers are determined experimentally by seeking best-fit between the rate expression and measured electroless deposition rates across wide concentration ranges, resulting in equations 1 and 2. The effect of transport was also incorporated in the model, as depletion near the surface changes the reactants concentration at the reaction site. To account for the transport dependence, electroless deposition experiments were performed on a rotating disk electrode (RDE). The model predicts that at lower rotation speed, both the surface concentrations of the reactants and the ensuing reaction rate will be lower. However, initially measured plating rates were significantly lower than predicted at the lower rotation rates. This was identified as being the consequence of partial surface blockage of the downward facing RDE by bubbles of hydrogen evolved in the reaction. Once the surface bubbles were eliminated, good agreement between the model predictions and actual measurements was noted, as shown in Fig. 2. The final result is a predictive, semi-empirical model for both deposition rate and the mixed potential for electroless plating which accounts for reactant concentrations and transport effects. More generally, this study presents a framework for characterizing other electroless systems for better understanding, scaling, and control of the process. Acknowledgements Atotech GMBH is acknowledged for funding this study and for providing helpful input. References Wagner, C., & Traud, W. (1938). On the Interpretation of Corrosion Processes through the Superposition of Electrochemical Partial Processes and on the Potential of Mixed Electrodes. Zeitschriff fur Elektrochemie.Yu, Lu, et al. "Autocatalysis during Electroless Copper Deposition using Glyoxylic Acid as Reducing Agent." Journal of the Electrochemmical Society (2013): D3004-D3008. Figure 1

ChemInform Abstract: Taming of Superacids: PVP‐Triflic Acid as an Effective Solid Triflic Acid Equivalent for Friedel—Crafts Hydroxyalkylation and Acylation.

Abstract The application of poly(4-vinylpyridine) supported trifluoromethanesulfonic acid (PVP-TfOH, 1:10) as a convenient solid superacid catalyst system in Friedel–Crafts reactions is described. In the presence of PVP-TfOH, one pot solvent-free synthesis of a wide variety of diarylacetic acid derivatives was achieved by Friedel–Crafts hydroxyalkylation reaction of glyoxylic acid with arenes under mild conditions. Acylation of both activated and deactivated aromatic compounds with acetyl chloride was also achieved using PVP-TfOH complex under solvent-free conditions at room temperature. As the polymer supported triflic acid was found to be a very efficient and an easy-to-handle solid acid, it can be a useful addition to environmentally more adaptable strong acid catalyst systems.

Development of Glyoxylic Acid Based Electroless Copper Deposition on Ruthenium

Glyoxylic acid is seen as a promising candidate to replace formaldehyde as reducing agent in electroless Cu baths. For deposition on ruthenium, the anodic reaction of glyoxylic acid has been evaluated and compared to formaldehyde using linear sweep voltammetry. Significant differences were observed for the deposition of copper on ruthenium. First of all, a faster nucleation to shorten the total process time, was inferred from open-circuit potential measurements. Secondary, we found 2,2’ bipyridyl worked as stabilizer, brightener, and suppressor in this glyoxylic acid-based electroless bath. Thirdly, the purity of the copper films improved when 2,2’ bipyridyl was present in the solution. Using the optimized composition for the electroless bath, we demonstrate a conformal Cu seed layer deposition (~100 nm) inside high aspect ratio (16.7) through Si vias. This work shows the potential for electroless Cu seeding for a through Si via metallization.

Experimental and Guided Theoretical Investigation of Complex Reaction Mechanisms in a Prins Reaction of Glyoxylic Acid and Isobutene

A laboratory experiment was designed for undergraduate students, in which the outcome of an easy single-step organic synthesis with well-defined conditions was not elucidated until the end of the exercise. In class, students predict and discuss the possible products using their knowledge of reaction mechanisms. In the laboratory, they learn how to carry out a reaction safely with gaseous isobutene, and to isolate and identify the two main products. The class and the laboratory components are completed in 10 h, including laboratory time of 6 to 7 h, divided in two sessions. The class-component could also be implemented independently as a theoretical exercise in a “virtual experiment” simply by presenting the methods and results to students using a guided-inquiry approach, appropriate for a standard 3 h undergraduate class. The finding that the simple reaction leads to a largely unexpected product, together with open discussions with students covering several theoretical aspects applicable to this reaction,...

ChemInform Abstract: Aqueous Organocatalyzed Aldol Reaction of Glyoxylic Acid for the Enantioselective Synthesis of α‐Hydroxy‐γ‐keto Acids.

AbstractGlyoxylic acid is used as an electrophile in the stereoselective aldol reactions with unfunctionalized cyclic and non‐cyclic ketones by using catalyst BPA.

Taming of superacids: PVP-triflic acid as an effective solid triflic acid equivalent for Friedel–Crafts hydroxyalkylation and acylation

The application of poly(4-vinylpyridine) supported trifluoromethanesulfonic acid (PVP-TfOH, 1:10) as a convenient solid superacid catalyst system in Friedel–Crafts reactions is described. In the presence of PVP-TfOH, one pot solvent-free synthesis of a wide variety of diarylacetic acid derivatives was achieved by Friedel–Crafts hydroxyalkylation reaction of glyoxylic acid with arenes under mild conditions. Acylation of both activated and deactivated aromatic compounds with acetyl chloride was also achieved using PVP-TfOH complex under solvent-free conditions at room temperature. As the polymer supported triflic acid was found to be a very efficient and an easy-to-handle solid acid, it can be a useful addition to environmentally more adaptable strong acid catalyst systems.

Nucleation Kinetics of Electroless Cu Deposition on Ruthenium Using Glyoxylic Acid as a Reducing Agent

Glyoxylic acid is seen as a promising candidate to replace formaldehyde as reducing agent in electroless Cu baths. For deposition on ruthenium, the anodic reaction of glyoxylic acid has been evaluated and compared to formaldehyde using linear sweep voltammetry. Significant differences were observed for the deposition of copper on ruthenium. First of all, a faster nucleation was inferred from open-circuit potential measurements, which is beneficial as it reduces the total process time. Secondary, we found 2,2′ bipyridyl worked as stabilizer and brightener in this glyoxylic acid-based electroless bath. Thirdly, the purity of the copper films improved when 2,2′ bipyridyl was present in the solution. Using the optimized composition, we demonstrate a conformal Cu seed layer deposition (∼100 nm) inside high aspect ratio (16.7) through-Si vias. This work shows the feasibility for electroless Cu seeding in a through-Si via metallization sequence.

Aqueous organocatalyzed aldol reaction of glyoxylic acid for the enantioselective synthesis of α-hydroxy-γ-keto acids

N-Tosyl-(Sa)-binam-L-prolinamide is an efficient catalyst for the aqueous aldol reaction, between glyoxylic acid, as monohydrate or aqueous solution, and ketones. This reaction led to the formation of chiral α-hydroxy-γ-keto carboxylic acids in high levels of diastereo- and enantioselectivities achieving mainly anti aldol products.

Dynamics and spectroscopy of vibrational overtone excited glyoxylic acid and 2,2-dihydroxyacetic acid in the gas-phase

The early time dynamics of vibrationally excited glyoxylic acid and of its monohydrate 2,2-dihydroxyacetic acid are investigated by theoretical and spectroscopic methods. A combination of "on-the-fly" dynamical simulations and cavity ring-down spectroscopy on the excited O-H stretching vibrational levels of these molecules observed that conformers that possess the correct structure and orientation react upon excitation of Deltaupsilon(OH)=4,5, while the structurally different but near isoenergetic conformers do not undergo unimolecular decay by the same direct and fast process. Experiment and theory give a femtosecond time scale for hydrogen atom chattering in the vibrationally excited glyoxylic acid. This process is the precursor for the concerted decarboxylation of the ketoacid. We extrapolate the results obtained here to suggest a rapid subpicosecond overall reaction. In these light-initiated reactions, relatively cold hydroxycarbenes, stable against further unimolecular decay, are expected products since most of the excitation energy is consumed by the endothermicity of the reaction. Glyoxylic acid and its monohydrate are atmospherically relevant ketoacids. The vibrational overtone initiated reactions of glyoxylic acid leading to di- and monohydroxycarbenes on subpicosecond time scales are potentially of importance in atmospheric chemistry since the reaction is sufficiently rapid to avoid collisional dissipation.

3,5-Bis(ethoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine-4-carboxylic acid

The title mol­ecule, C14H19NO6, was synthesized by the reaction of glyoxylic acid, ethyl acetoacetate and NH4HCO3. In the crystal structure, the dihydro­pyridine ring adopts an asymmetric boat-type conformation with the C atom bearing the carboxyl group showing a signficantly larger deviation [0.325 (2) Å] from the base plane then the N atom [0.137 (2) Å]. One of the ethyl groups is disordered over two positions with occupancies of 0.741 (10) and 0.259 (10). The crystal is stabilized by strong inter­molecular hydrogen bonds. N—H⋯O inter­actions form infinite chains in the a direction. O—H⋯O hydrogen bonds form typical carboxylic acid dimers, which link the N—H⋯O chains into a ladder-type double chain.

Infrared Spectroscopic Study of Adsorption and Reactions of Glyoxylic Acid on TiO2

Fourier transform infrared spectroscopy has been employed to investigate the adsorption, thermal reactions, and photodegradation of glyoxylic acid on TiO2 in a gas−solid system. Glyoxylic acid may exist on TiO2 at 35 °C with several dissociative adsorption forms, through the interaction of the carboxyl group or the diol group derived from carbonyl transformation. CO, CO2, HCOO (formate), and CH3O (methoxy) are found to be the thermal reaction products. A C−C bond scission pathway is proposed for the formation of CH3O via −OCH2O− (dioxymethylene), which can undergo self oxidation−reduction. However, another possible route producing oxalic acid or oxalate is not important. Moreover, O2 has no effect on the decomposition of the surface glyoxylic acid and on the formation temperature of the thermal reaction products. In the photochemistry of glyoxylic acid on TiO2 irradiated at 400 nm, it produces CO2, carbonate, and HCOO. O2 can enhance the formation of CO2 and carbonate species. The 18O2 isotopic study shows that the CO2 and carbonates formed in the initial photoirradiation stage (≤10 min) may only contain a small amount of 18O. The role dioxygen may play in the initial photodecomposition of glyoxylic acid on TiO2 is to capture the photogenerated electrons, increasing the lifetime of holes and thus the photooxidation efficiency, but hardly directly participating in the product formation.

THEORETICAL STUDY ON THE UNIMOLECULAR REACTIONS OF GLYOXYLIC ACID

The potential energy surfaces of isomerization, decarboxylation, and decarbonylation reactions of glyoxylic acid have been characterized by the B3LYP/cc-pVTZ, B3LYP/aug-cc-pVTZ, and MP2/cc-pVTZ calculations. There is a relatively high barrier on the isomerization pathway from Tc to Tt , due to existence of the intramolecular H-bond in the Tc to Tt structures. The decarboxylation reaction proceeds mainly through a stepwise mechanism. The singlet hydroxyl carbene and carbon dioxide are formed in the first step, which is followed by isomerization of the carbene to formaldehyde in the second step. The thermal decarbonylation reaction of glyoxylic acid may take place at high temperature, due to a barrier of ~52 kcal/mol on the pathway.

Synthesis of novel protected Nalpha(omega-thioalkyl) amino acid building units and their incorporation in backbone cyclic disulfide and thioetheric bridged peptides.

General methods for the preparation of protected Nalpha(omega-thioalkyl) amino acids building units for backbone cyclization using reductive alkylation and on-resin preparation are described. The synthesis of non-Gly Fmoc-protected S-functionalized N-alkylated amino acids is based on the reaction of readily prepared protected omega-thio aldehyde with the appropriate amino acid. Preparation of Fmoc-protected S-functionalized N-alkylated Gly building units was carried out using two methods: reaction of glyoxylic acid with Acm-thioalkylamine and an on-resin reaction of bromoacetyl resin with Trt-thioalkylamines. Three model peptides were prepared using these building units. The GlyS2 building unit was incorporated into a backbone cyclic analog of somatostatin that contains a disulfide bridge. Formation of the disulfide bridge was performed by on-resin oxidation using 12 or Tl(CF3COO-)3. Both methods resulted in the desired product in a high degree of purity in the crude. The AspS3 building unit was also successfully incorporated into a model peptide. In addition, the in situ generation of sulfur containing Gly building units was demonstrated on a Substance P backbone cyclic analog containing a thioether bridge.

Reactions of glyoxylic acid with aliphatic alcohols using cationic exchange resins as catalysts

The reactions of glyoxylic acid with different aliphatic alcohols were studied in the presence of both gelular and macroporous ion exchange resins as catalysts. The alcohol reacts with both acid and aldehyde group of glyoxylic acid to form ester and the acetal of the ester, respectively. The simultaneous removal of water during the course of the reaction, helps in increasing the conversion level. An increase in temperature leads to better selectivity towards the acetal of the ester. The kinetics of the extractive reactions (solid–liquid–liquid mode) of aqueous solution of glyoxylic acid with 2-ethyl hexanol was studied and a significant level of conversion was obtained even with dilute (5% w/w) solution. A pseudohomogeneous kinetic model explains the data successfully.

A method for counterstaining tissues in conjunction with the glyoxylic acid condensation reaction for detection of biogenic amines.

A method is described for counterstaining tissue for use with the glyoxylic acid reaction for visual detection of biogenic amines. Counterstaining is achieved by addition of the fluorescent dye malachite green to the sucrose-phosphate-glyoxylic acid (SPG) solution used for processing of cryostat sections of unfixed tissues. When bound to tissues, the dye provides red-orange fluorescence of background tissue, which contrasts well with the green to yellow fluorescence induced by the glyoxylic acid reaction product formed with biogenic amines. The counterstaining technique is demonstrated in a number of catecholamine-containing peripheral tissues and is compared to sections that were processed without counterstaining.