Hydroxy Aldehydes Research Articles

Synthesis of (±)-Protoconstipatic acid methyl ester

Protoconstipatic acid methyl ester was synthesized from the readily available dimethyl itaconate–anthracene adduct as a building block; reacted with the novel protected hydroxy aldehyde via tandem aldol‒lactonization, isomerization and pyrolysis, respectively, producing 23% overall yield.

Temperature-Dependent Oxidation of Hydroxylated Aldehydes by •OH, SO4•-, and NO3• Radicals in the Atmospheric Aqueous Phase.

T-dependent aqueous-phase rate constants were determined for the oxidation of the hydroxy aldehydes, glyceraldehyde, glycolaldehyde, and lactaldehyde, by the hydroxyl radicals (•OH), the sulfate radicals (SO4•-), and the nitrate radicals (NO3•). The obtained Arrhenius expressions for the oxidation by the •OH radical are: k(T,GLYCERALDEHYDE+OH•) = (3.3 ± 0.1) × 1010 × exp((-960 ± 80 K)/T)/L mol-1 s-1, k(T,GLYCOLALDEHYDE+OH•) = (4.3 ± 0.1) × 1011 × exp((-1740 ± 50 K)/T)/L mol-1 s-1, k(T,LACTALDEHYDE+OH•) = (1.6 ± 0.1) × 1011 × exp((-1410 ± 180 K)/T)/L mol-1 s-1; for the SO4•- radical: k(T,GLYCERALDEHYDE+SO4•-) = (4.3 ± 0.1) × 109 × exp((-1400 ± 50 K)/T)/L mol-1 s-1, k(T,GLYCOLALDEHYDE+SO4•-) = (10.3 ± 0.3) × 109 × exp((-1730 ± 190 K)/T)/L mol-1 s-1, k(T,LACTALDEHYDE+SO4•-) = (2.2 ± 0.1) × 109 × exp((-1030 ± 230 K)/T)/L mol-1 s-1; and for the NO3• radical: k(T,GLYCERALDEHYDE+NO3•) = (3.4 ± 0.2) × 1011 × exp((-3470 ± 460 K)/T)/L mol-1 s-1, k(T,GLYCOLALDEHYDE+NO3•) = (7.8 ± 0.2) × 1011 × exp((-3820 ± 240 K)/T)/L mol-1 s-1, k(T,LACTALDEHYDE+NO3•) = (4.3 ± 0.2) × 1010 × exp((-2750 ± 340 K)/T)/L mol-1 s-1, respectively. Targeted simulations of multiphase chemistry reveal that the oxidation by OH radicals in cloud droplets is important under remote and wildfire influenced continental conditions due to enhanced partitioning. There, the modeled average aqueous •OH concentration is 2.6 × 10-14 and 1.8 × 10-14 mol L-1, whereas it is 7.9 × 10-14 and 3.5 × 10-14 mol L-1 under wet particle conditions. During cloud periods, the aqueous-phase reactions by •OH contribute to the oxidation of glycolaldehyde, lactaldehyde, and glyceraldehyde by about 35 and 29%, 3 and 3%, and 47 and 37%, respectively.

Looking in Depth at Oxidized Cholesteryl Esters by LC-MS/MS: Reporting Specific Fragmentation Fingerprints and Isomer Discrimination.

Cholesteryl esters (CE) are prone to oxidation under increased oxidative stress conditions, but little is known about oxidized CE species (oxCE). To date, only a few oxCE have been identified, however, mainly based on the detection of molecular ions by mass spectrometry (MS) or target approaches for specific oxCE. The study of oxCE occurring from radical oxidation is still scarcely addressed. In this work, we made a comprehensive assessment of oxCE derivatives and their specific fragmentation patterns to identify detailed structural features and isomer differentiation using high-resolution C18 HPLC-MS- and MS/MS-based lipidomic approaches. The LC-MS/MS analysis allowed us to pinpoint oxCE structural isomers of long-chain and short-chain species, eluting at different retention times (tR). Data analysis revealed that oxCE can be modified either in the fatty acyl moiety or in the cholesterol ring. The location of the hydroxy/hydroperoxy group originates characteristic fragment ions, namely the unmodified cholestenyl cation (m/z 369) for the isomer with oxidation in the fatty acyl chain or ions at m/z 367 and m/z 385 (369 + 16) when oxygenation occurs in the cholesterol ring. Additionally, we identified CE 18:2 and 20:4 aldehydic and carboxylic short-chain products that showed a clear fragmentation pattern that confirmed the modification in the fatty acyl chain. Specific fragmentation fingerprinting allowed discrimination of the isobaric short-chain species, namely carboxylic short-chain products, from hydroxy aldehyde short-chain products, with a hydroxycholesterol moiety. This new information is important to identify different oxCE in biological samples and will contribute to unraveling their role in biological conditions and diseases such as cardiovascular disease.

Study of the transition metal complexes with novel Schiff bases and their biological activity

The Sysnthesis of novel Schiff base from substituted aminothiazole i.e. 5-methyl 2-4 Diamino thiazole and substituted hydroxy aldehyde i.e. R=H, and 5-CH3 and transition metal ion CoII, NiII, CuII & ZnII. Etc. their characterization were mode by elemental analysis i.e. uv visible and IR spectra, magnetic susceptibility and conductivity measurement. The complexes are monomeric as well as dimeric in nature. The ligand coordinate through oxygenatom of phenolic – OH group and ring nitrogen with azomethine group (-C=N-) the complexes are non-electrolyte in nature. The Schiff bases and transition metal complexes are screen for antimicrobial, fungicidal and pesticidal activity.

Enzymic Aldol Reactions of Aliphatic Nucleophiles and Hydroxy Aldehydes

Enzymic Aldol Reactions of Aliphatic Nucleophiles and Hydroxy Aldehydes

Pyrolysis oil polymerization of water-soluble fraction during accelerated aging

Pyrolysis oil is a promising material for renewable energy through a hydrogenation process. However, the polymerization, initiated especially by pyrolysis oil water-soluble fraction (PS), is a big hurdle to hydrogenation. The types and structures of the polymerization chemicals, their polymerization mechanisms are very important for upgrading pyrolysis oil. This study firstly compared the polymerization rates of water-soluble fraction (PS) and water-insoluble fraction (PL) by accelerating aging fresh PS and PL at different temperatures (80 °C, 90 °C, 100 °C and 110 °C) for 24 h and at 110 °C for different durations (12 h, 24 h, 36 h, 48 h and 60 h), respectively. The thermogravimetric and differential thermogravimetry analysis results showed that PS polymerized much more rapidly than PL. Then, PS polymerization was further investigated by evaluating the changes in its physical properties (water content, viscosity and element content) and chemical compositions (gas chromatography and liquid chromatogram) before and after aging. The results showed that hydroxy aldehydes and ketones (especially glycoaldehyde, hydroxyacetone and levoglucosan), dicarbonyl compounds (especially succindialdehyde) and α, β-unsaturated carbonyl compounds (especially 3-methyl-2-cyclopenten-1-one and dehydrate resultants of some aldol condensation products) were mainly responsible for PS polymerization.

Second Generation of Aldol Reaction.

Since the discovery of the Mukaiyama aldol reaction more than 40 years ago, several landmark publications have inspired researchers in the field. The Mukaiyama AR is one of the most significant named reactions in organic synthesis. In the past few decades, development of the modern AR has been at the forefront in addressing the challenges of regio-, chemo-, diastereo-, and enantioselectivity in organic synthesis. All of these selectivity challenges maybe present in a single pair of reactants, thus controlling the outcome of such a process has great practical value. More than 10 years ago, our group became involved in this iconic carbon-carbon bond-forming process and attempted to very closely investigate all possible features of the AR to solve several issues still encountered by chemists, most notably the selectivity challenges mentioned above. In this context, our group initiated the second generation of the AR based on a Lewis or Brønsted acid-catalyzed process in conjunction with the use of a "super silyl" (tris(trimethylsilyl)silyl) directing group, which has demonstrated unrivalled properties in controlling the outcome of the AR. Using the extraordinary power of the super silyl group, we were able to develop new methods and concepts that broadly impacted the ability to control the selectivity attributes and thus allowed for a highly stereoselective construction of polyketide, halogenated polyketide, polypropionate, and polyol scaffolds through inter- and/or intramolecular aldolization protocols. Our diastereoselective ARs of super silyl enol ethers and aldehydes have shown great efficiency and modularity in producing exclusively and preferentially syn- or anti-adducts, creating up to four new adjacent stereocenters in a one-pot sequential manner and under mild reaction conditions. The super silyl-directed AR does not only provide a solution to stereochemistry control challenges, but also offers an efficient, modular and high yielding technique toward nontrivial construction of complex architectures with unprecedented ease. We believe that the new Lewis- or Brønsted-acid-catalyzed super-silyl-directed AR processes chronicled in our laboratories have come to maturity and now offer a "road map" for strategic stereoselective synthesis of polyketide-like units. Herein we report our recent achievements in the diastereoselective C-C bond formation, through the super-silyl-directed AR, toward the synthesis of complex and sophisticated hydroxy aldehydes. We would like to note that due to the extremely broad range of work reported in this field, only stereoselective AR involving aldehyde-derived super SEEs will be discussed in this Account.

A Diet with 3% of Energy from a Mixture of Omega-3 Fatty Acids Significantly Increases <i>in Vivo</i> Lipid Peroxidation in Postmenopausal Women

Dietary omega-3 (n - 3) polyunsaturated fatty acids (PUFA) are recommended by public health organizations to reduce the risk of cardiovascular disease, and several epidemiological studies have suggested there is an inverse association between n - 3 intake and human cancers. However, n - 3 are susceptible to an increase in lipid peroxidation in the human body. As part of a crossover dietary intervention study of a diet (20% of energy from fat) with or without an additional 3% of energy from a mixture of n - 3 (with 5.36 g α-linolenic acid and 1.45 g eicosapentaenoic acid and docosahexaenoic acid per 2000 kcal per day), we measured total in vivo lipid peroxidation in healthy postmenopausal women (n = 15). Our results indicated that the diet with 3% of energy from n - 3 significantly increased the urinary concentrations of total polar lipophilic aldehydes and related compounds produced via lipid peroxidation (p α, β-unsaturated hydroxy aldehydes 4-hydroxy-2-trans - hexenal (p trans -decenal (p trans -decenal in the urine of individuals consuming n - 3. These results demonstrate that an increase in 3% of energy from dietary n – 3 increases in vivo lipid peroxidation.

Chirality induction and chiron approaches to enantioselective total synthesis of α-lipoic acid

An efficient, short and convenient asymmetric synthesis of (R)-(+)-lipoic acid in seven steps from chiral hydroxy aldehyde with 32.5% overall yield is described. Synthesis of S and R enantiomers of α-lipoic acid from cis-1,4-butene diol derived chiral lactone is reported with 34 % overall yield. The present synthesis involves use of simple reaction conditions making it a convenient synthesis.

Adsorption of Cu(II) and Zn(II) Ions by Solidified Landfilled Sludge and its Pyrolyzed Produce

In this study, using solidified landfilled sludge (SLS) and its pyrolyzed produce (PSLS) as adsorbents, adsorption characteristics of Cu2+ and Zn2+ onto SLS and PSLS was investigated. These results revealed that PSLS had more irregular pores and its surface roughness increased, and the surface area of PSLS was twice than that of SLS. Adsorption studies showed that adsorption capacity of Cu2+ and Zn2+ increased with the increasing dosage of adsorbents, and the adsorption process of Cu2+ and Zn2+ onto SLS or PSLS could be divided into the first rapid step and the second slower step. Based on Langmuir equation, the maximum limiting adsorption capacities of Cu2+ and Zn2+ onto PSLS was much higher that onto SLS. Moreover, FTIR analysis showed that the adsorption of Cu2+ and Zn2+ on SLS depended on active functional group such as hydroxy aldehydes while that relied on the groups such as C=C bond of aromatic rings, Si-O-Si or Si-O-C structures for PSLS.

Synthesis of silicon-containing monomers with aldehyde groups

Silicon-containing monomers with different functional groups are used in the synthesis of heat and corrosion resistant polymers, as well as modifiers for various polymers to improve their operational characteristics [1–3]. The goal of the present work was to synthesize silicon-containing monomers functionalized with aldehyde groups, which may be used for the preparation of polymers with enhanced heat and frost resistance and tensile strength as compared to carboxycontaining polymers [3]. The procedure developed by us for the synthesis of such monomers is based on the reaction of trichloro(phenyl)silane with hydroxy aldehydes. The reaction of trichloro(phenyl)silane with β-hydroxybutyraldehyde gave tris-butanal I (Scheme 1). alcohols, ketones, and ethers and insoluble in aliphatic hydrocarbons and water.

Facile Synthesis of Furowarfarins via Hetero-Diels–Alder Cycloaddition Reaction

Synthesis of new furowarfarins has been carried out via tandem Knoevenagel–hetero-Diels–Alder cycloaddition reaction. One-pot, multicomponent reaction involving, heating a mixture of hydroxy chromenone, aldehyde, and 2-methoxy propene afforded pyranochromenone with good diastereoselectivity, favoring the exo (trans) cycloadduct, in contrast to previous literature reports. The pyran ring exists in a half-chair conformation with C9-OMe in ψ-axial and C7-phenyl ring in ψ-equatorial positions. Single-crystal x-ray analysis conclusively confirms the structure.

ChemInform Abstract: Oxidation of Alcohols to Carbonyl Compounds with Diisopropyl Azodicarboxylate Catalyzed by Nitroxyl Radicals.

AbstractThe simple, mild, and efficient method for the oxidation of alcohols to aldehydes and ketones includes a selective formation of diketones, hydroxy aldehydes, and hydroxy ketones from diols.

Investigation of the degradation of cresols in the treatments with ozone

The reaction between ozone and the three cresol isomers was investigated in pure water. Cresols were selected as model substrates representing an important component of humic material. Cresols carry both a hydroxyl and a methyl group, each theoretically increasing the reactivity of ozone with the aromatic ring. Direct comparison of the aromatic ring and the methyl group reactivities was made possible by the analysis of reaction products. The substrate degradation kinetics was studied by preparing aqueous solutions of each cresol and treating them with ozone for increasing time periods. It had been hypothesized that hydroxybenzaldehydes and hydroxybenzoic acids could be possible degradation intermediates of cresols. To verify this hypothesis, the degradation kinetics of three hydroxybenzaldehydes and two hydroxybenzoic acids were also studied. The reaction products were studied using gas chromatography (GC)-electron capture negative ionization (ECNI)-mass spectrometry (MS) analysis after direct derivatization of the samples with 5-chloro-2,2,3,3,4,4,5,5-octafluoro-1-pentyl chloroformate (ClOFPCF). This new analytical approach enables the extraction and analysis of highly polar polycarboxylic and hydroxycarboxylic acids, as well as highly polar aldehydes and hydroxy aldehydes that are difficult to extract and measure using conventional methods. As such, this new approach offered insights into ozone reaction intermediates that had been previously hypothesized, but not confirmed. Several highly hydrophilic degradation intermediates were identified, including malic, citraconic, itaconic, malonic, methylmuconic, and tartronic acid, but no hydroxybenzaldehydes were observed. The results support a 3-stage mechanism previously hypothesized, which involves ring-opening of the phenolic group, followed by the generation of several intermediates of increasing oxidation state, finally leading to relatively stable products, such as malonic and oxalic acids. We demonstrated that oxidation of the methyl group does not occur during cresol degradation.

Aryl[2.2]paracyclophane‐Based Chiral Regioisomeric Analogs of Salicyl Aldehyde: Novel Sources for Construction of Phenoxy‐Imine Ligands

AbstractThe efficient, high‐yield approaches to two novel regioisomeric salicyl aldehyde analogs, 4‐formyl‐13‐(2‐hydroxyphenyl)‐[2.2]paracyclophane and 4‐formyl‐12‐(2‐hydroxyphenyl)‐[2.2]paracyclophane (iso‐FHPhPC and pseudo‐FHPhPC, respectively), constructed on the basis of an aryl[2.2]paracyclophane backbone are described. The key stage of the backbone formation is the Suzuki cross‐coupling of paracyclophanyl halides with arylboronic acids. Efficient procedures for the resolution of the racemic hydroxy aldehydes into enantiomers via Schiff bases with enantiomers of α‐phenylethyl amine were elaborated, and the absolute configurations of enantiomers were established on the basis of X‐ray analysis of diastereomeric imines. Starting from these chiral hydroxy aldehydes the first representatives of bi‐, tri‐, and tetradentate phenoxy‐imine ligands belonging to an aryl[2.2]paracyclophane family were obtained. The induction power of the ligands was tested in the Et2Zn asymmetric addition to aldehydes.

Novel 4(3H)-quinazolinones containing biologically active thiazole, pyridinone and chromene of expected antitumor and antifungal activities

Novel 4(3 H )-quinazolinone derivatives with biologically active moieties were synthesized. Reactions of 2-cyano- N -(6-iodo-2-methyl-4-oxoquinazolin-3(4 H )-yl) acetamide with carbon disulfide, isothiocyanates followed by cycloalkylation afforded acrylamide, 1,3-dithiazole, 1,3-dithiane, thiazole and pyrazole derivatives. The 2-pyridone derivatives were obtained via reaction of cyanoacetamide with some acetylacetone or arylidenes. Cyclocondensation reaction of cyanoacetamide with o -hydroxy aldehydes furnished chromene derivatives. Screening for some selected compounds was carried for their potential antitumor and antifungal activities. 2-Cyano- N -(6-iodo-2-methyl-4-oxoquinazolin-3(4 H )-yl)-2-(4-methyl-3-phenyl-thiazol-2(3 H )ylidene)-acetamide with 3-side chain incorporated with substituted thiazole moiety was found to be of high to moderate activity towards cells. Also, the latter product showed high activity against Aspergillus ochraceus Wilhelm with inhibition zone (18 mm) compared with (20 mm) Nystatin inhibition zone.

Ruthenium(II) hydrazone Schiff base complexes: Synthesis, spectral study and catalytic applications

Ruthenium(II) hydrazone Schiff base complexes of the type [RuCl(CO)(B)(L)] (were B = PPh 3, AsPh 3 or Py; L = hydrazone Schiff base ligands) were synthesized from the reactions of hydrazone Schiff base ligand (obtained from isonicotinoylhydrazide and different hydroxy aldehydes) with [RuHCl(CO)(EPh 3) 2(B)] (where E = P or As; B = PPh 3, AsPh 3 or Py) in 1:1 molar ratio. All the new complexes have been characterized by analytical and spectral (FT-IR, electronic, 1H, 13C and 31P NMR) data. They have been tentatively assigned an octahedral structure. The synthesized complexes have exhibited catalytic activity for oxidation of benzyl alcohol to benzaldehyde and cyclohexanol to cyclohexanone in the presence of N-methyl morpholine N-oxide (NMO) as co-oxidant. They were also found to catalyze the transfer hydrogenation of aliphatic and aromatic ketones to alcohols in KOH/Isopropanol.

Correlation analysis of reactivity in the oxidation of some organic diols by tripropylammonium fluorochromate in non-aqueous media

The kinetics of oxidation of some organic diols by tripropylammonium fluorochromate (TriPAFC) have been studied in dimethylsulfoxide (DMSO). The main product of oxidation is the corresponding hydroxy aldehydes. The reaction is first order with respect to TriPAFC and exhibited Michaelis-Menten type kinetics with respect to organic diols. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs=a+b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of diols was studied in 18 different organic solvents. The rate data are showing satisfactory correlation with Kamlet–Taft solvotochromic parameters (α, β and π∗). A suitable mechanism of oxidation has been proposed.

ChemInform Abstract: Applications of Optically Active Aryl Cyanohydrins in the Synthesis of α-Hydroxy Aldehydes, α-Hydroxy Ketones and β-Hydroxy Amines.

Cyanohydrins, prepared in high optical purity from aryl aldehydes, have been converted into α- hydroxy aldehydes, β- hydroxy ketones and β- hydroxy amines without any racemization and frequently with good stereoselectivity for the erythro-diastereoisomer (>90%) at the newly introduced stereogenic centre.

ChemInform Abstract: Enzyme-Catalyzed Reactions. Part 10. Synthesis of O-Protected (R)-2- Hydroxy Aldehydes and Their Hydrocyanation.

ChemInform Abstract: Enzyme-Catalyzed Reactions. Part 10. Synthesis of O-Protected (R)-2- Hydroxy Aldehydes and Their Hydrocyanation.