Mixture Of Aldehydes Research Articles

Quantitative NMR spectroscopy of binary liquid mixtures (aldehyde + alcohol). Part III: (1-decanal or 3-phenylpropanal or 2-chlorobenzaldehyde) + (methanol or ethanol or 1-propanol)

The thermodynamic properties of binary liquid mixtures of (aldehyde+alcohol) are strongly influenced by chemical reactions in particular around and below ambient temperature. In two previous publications the chemical reaction equilibrium was investigated by 13C – Fourier transform NMR-spectroscopy at temperatures between 255K and 295K for a series of aldehydes (acetaldehyde, 1-propanal, 1-butanal, 1-heptanal) with three alcohols (methanol, ethanol, 1-propanol). Here these investigations are extended to three more aldehydes (1-decanal, 3-phenylpropanal and 2-chlorobenzaldehyde, respectively). The results for the binary systems with decanal or 3-phenylpropanal as the aldehyde in the binary mixture (aldehyde+alcohol) confirm the expectations from the first parts of this series, i.e., that the majority of the constituents of the mixture is present as hemiacetal and the first two poly(oxymethylene) – hemiacetals. The numerical results for the chemical reaction equilibrium constants from the previous investigations can be used to predict quantitatively the speciation in binary systems of ((either 1-decanal or 3-phenylpropanal)+(either methanol or ethanol or 1-propanol)). However the experimental results with 2-chlorobenzaldehyde reveal a different behaviour. In all investigated systems (2-chlorobenzaldehyde+alcohol) the most important reaction product was the corresponding acetal whereas the amounts of hemiacetal were very small. While the amounts of hemiacteal could still be quantified, it was not possible to quantify the amount of any poly(oxymethylene) – hemiacetal.

Decarboxylative Trichloromethylation of Aromatic Aldehydes and Its Applications in Continuous Flow

Two new protocols for the efficient synthesis of 2,2,2-trichloromethylcarbinols, starting from aromatic aldehydes, have been developed. A combination of sodium trichloroacetate in the presence of malonic acid proved efficient for the transformation of electron deficient aldehydes using DMSO as solvent. Electron-rich aldehydes did, however, not require the addition of malonic acid, affording the desired 2,2,2-trichloromethylcarbinols without a trace of the competing Cannizzaro reaction. Finally, the reaction of sodium trichloroacetate in THF with a mixture of aldehyde and malonic acid dissolved in DMSO allowed the protocol to be performed in continuous flow. By performing this decarboxylative reaction in continuous flow, scale-up of the reaction could be achieved with a simple and safe setup. In this flow setup, four electron-deficent aldehydes were successfully transformed into their 2,2,2-trichloromethylcarbinol derivatives on a 100 mmol scale.

Synthesis and antibacterial activity of 5-aryl-4-acyl-3-hydroxy-1-(2-hydroxyethyl)-3-pyrrolin-2-ones

5-Aryl-4-acyl-3-hydroxy-1-(2-hydroxyethyl)-3-pyrrolin-2-ones were synthesized using the reaction of ethanolamine with a mixture of aromatic aldehyde and methyl acylpyruvates. The antibacterial activity of the synthesized compounds was studied.

Synthesis and Biological Activity of 5-aryl-4-acyl-3-hydroxy-1-(2-piperazin-1-ylethyl)-2,5-dihydropyrrol-2-ones and their Derivatives

5-Aryl-4-acyl-3-hydroxy-1-(2-piperazin-1-ylethyl)-2,5-dihydropyrrol-2-ones (I) were synthesized by reactions of acylpyruvate methyl esters with a mixture of aromatic aldehyde and 2-(1-piperazino)-1-ethylamine. Then, the corresponding hydrochlorides (II) were obtained. Compounds I were transformed into 3,4-diaryl-4,6-dihydro-5-(2-piperazin-1-ylethyl)pyrrolo[3,4-c]pyrazol-6-ones (III) by reaction with hydrazine hydrate. The antimicrobial activity of compounds I and the influence of compounds II and III on blood coagulation were studied. The acute toxicity of two compounds was evaluated.

Chemical Composition and Cytotoxic Activities of Petroleum Ether Fruit Extract of Fruits of <i>Brucea javanica</i> (Simarubaceae)

Purpose: To investigate the chemical composition and antitumor activity of the petroleum ether extract of the dried ripe fruits of Brucea javanica. Methods: The composition of petroleum ether extract was analyzed by gas chromatography/mass spectrometric (GC/MS) and their antitumor activities were determined by MTT assay. Results: GC/MS spectrometry results indicate that the petroleum ether extract was a mixture of esters, fatty acids, sterides, pregnanones, terpenes, alkaloids, alkenes, alcohols, ketones, aldehydes and other compounds. The results also revealed the significant antitumor activity of the extract with IC50 of 9.14, 12.45, 15.15, 16.13, 22.26, and 27.97 μg/mL against A549, CNE, MCF-7, NCI-H460, HepG2, and KB-3-1 cell lines, respectively. Conclusion: The study establishes the chemical composition and cytotoxic activity of the petroleum ether extract of the plant fruits. There is need for further investigations to isolate more potent compounds and structurally modify the known compounds to retain activity and lower toxicity and thus lead to the possible development of Brucea javanica oil.

ChemInform Abstract: Ruthenium‐Catalyzed Oxidation of Alcohols by Bromate in Water.

AbstractAn efficient catalyst is applied to the oxidation of secondary‐ and primary alcohols to the corresponding ketones (II) or mixtures of aldehydes (IV) and carboxylic acids (V) with excellent conversions at room temperature.

Synthesis and Antibacterial Activity of 1-(4-Aminosulfonylphenyl)-5-aryl-4-acyl-3-hydroxy-3-pyrrolin-2-ones

A series of 1-(4-aminosulfonylphenyl)-5-aryl-4-acyl-3-hydroxy-3-pyrrolin-2-ones have been synthesized by the reaction of methyl esters of acylpyruvic acids with a mixture of aromatic aldehyde and 4-aminobenzenelsulfamide. The proposed structures are confirmed by 1 H NMR and IR spectroscopy. The re- sults of investigations of the antibacterial activity of the synthesized compounds are presented.

Biomass pyrolysis: Thermal decomposition mechanisms of furfural and benzaldehyde

The thermal decompositions of furfural and benzaldehyde have been studied in a heated microtubular flow reactor. The pyrolysis experiments were carried out by passing a dilute mixture of the aromatic aldehydes (roughly 0.1%-1%) entrained in a stream of buffer gas (either He or Ar) through a pulsed, heated SiC reactor that is 2-3 cm long and 1 mm in diameter. Typical pressures in the reactor are 75-150 Torr with the SiC tube wall temperature in the range of 1200-1800 K. Characteristic residence times in the reactor are 100-200 μsec after which the gas mixture emerges as a skimmed molecular beam at a pressure of approximately 10 μTorr. Products were detected using matrix infrared absorption spectroscopy, 118.2 nm (10.487 eV) photoionization mass spectroscopy and resonance enhanced multiphoton ionization. The initial steps in the thermal decomposition of furfural and benzaldehyde have been identified. Furfural undergoes unimolecular decomposition to furan + CO: C4H3O-CHO (+ M) → CO + C4H4O. Sequential decomposition of furan leads to the production of HC≡CH, CH2CO, CH3C≡CH, CO, HCCCH2, and H atoms. In contrast, benzaldehyde resists decomposition until higher temperatures when it fragments to phenyl radical plus H atoms and CO: C6H5CHO (+ M) → C6H5CO + H → C6H5 + CO + H. The H atoms trigger a chain reaction by attacking C6H5CHO: H + C6H5CHO → [C6H6CHO]* → C6H6 + CO + H. The net result is the decomposition of benzaldehyde to produce benzene and CO.

Oxygenation of Ruthenium Carbene Complexes Containing Naphthothiophene or Naphthofuran: Spectroscopic and DFT Studies

The aryl propargylic alcohol 1-[2-(thiophen-3-yl)phenyl]prop-2-yn-1-ol (1a) is readily prepared from 2-(thiophen-3-yl)benzaldehyde. In the presence of visible light, treatment of 1a with one-half mole equivalent of [Ru]Cl ([Ru]=Cp(dppe)Ru) (dppe=1,2-bis(diphenylphosphino)ethane) and NH4PF6 in O2 affords the naphtha[2,1-b]thiophene-4-carbaldehyde (4a) in high yields. The cyclization reaction of 1a proceeds through the formation of the carbene complex 2a that contains the naphtha[2,1-b]thiophene ring, which is isolated in a 1:1 stoichiometric reaction. The C-C bond formation between the inner carbon of the terminal triple bond and the heterocyclic ring is confirmed by structure determination of 2a using single-crystal X-ray diffraction analysis. Facile oxygenation of 2a by O2 yields the aldehyde product 4a accompanied by the formation of phosphine oxide of dppe. Oxygen is most likely activated by coordination to the ruthenium center when one PPh2 unit of the dppe ligand dissociates. This dissociated PPh2 unit then reacts with the coordinated oxygen nearby to generate half-oxidized dppe ligand and an unobserved oxo-carbene intermediate. Coupling of the oxo/carbene ligands followed by demetalation then yields 4a. Presumably the resulting complex with the half-oxidized dppe ligand continuously promotes cyclization/oxygenation of 1a to yield the second aldehyde molecule. In alcohol such as MeOH or EtOH, the oxygenation reaction affords a mixture of 4a and the corresponding esters 5a or 5a'. Four other aryl propargylic alcohols 1b-e, which contain thiophen-2-yl, isopropenyl, fur-3-yl, and fur-2-yl, respectively, on the aryl ring are also prepared. Analogous aldehydes 4b-e are similarly prepared from 1b-e, respectively. For oxygenations of 1b, 1d, and 1e in alcohol, mixtures of aldehyde 4, ester 5, and acetal 8 are obtained. The carbene complex 2b obtained from 1b was also characterized by single-crystal X-ray diffraction analysis. The UV/Vis spectra of 2a and 2b consist of absorption bands with a high extinction coefficient. From DFT calculations on 2a and 2b, the visible light is found to populate the LUMO antibonding orbital of mainly Ru=C bonds, thereby weakening the Ru=C bond and promoting the oxygenation/demetalation reactions of 2.

Characteristics of TVOC, Aldehydes and Ketones Emitted from Fiber Hot-Pressing in Manufacturing of MDF made from Poplar and Pine

This study, by means of GC-MS and HPLC, investigated the characteristics of volatile organic compounds (VOCs) released from fiber hot-pressing in a medium density fiberboard (MDF) production line with a production capacity of 80,000 m3/a. The quantity of total volatile organic compounds (TVOC), aldehydes and ketones were calculated. The results showed that the concentration of TVOC reached 1.8940 mg/m3. The main components include terpenes, acrolein and acetone, benzenes series and saturated hydrocarbons. The concentration of the mixture of aldehydes and ketones was 5.1136 mg/m3.

Synthesis of 4-(4-methoxyphenyl)-2,6-dinitrobenzaldehyde

Photoacid generators capable of undergoing decomposition under irradiation with visible light are very important for efficient oligonucleotide microarray fabrication. In this case, there are no detrimental effect of UV irradiation on growing oligonucleotide chain and related side reactions leading to degradation of targeted oligonucleotides [1, 2]. An important intermediate product in the synthesis of photoacids necessary for the preparation of oligonucleotide bioarrays is 4-(4-methoxyphenyl)-2,6-dinitrobenzaldehyde, which was previously synthesized by oxidation of 2-bromomethyl-5(4-methoxyphenyl)-1,3-dinitrobenzene (I) with bis(tetrabutylammonium) dichromate on prolonged heating in boiling chloroform; however, the yield of II was as poor as 23% [2]. The goal of the present work was to develop a procedure which could be the most convenient for the preparation of 4-(4-methoxyphenyl)2,6-dinitrobenzaldehyde. The transformation of benzyl halides into the corresponding aldehydes is widely used in synthetic organic chemistry [3–5]. Benzyl halides can be converted into aldehydes via oxidation according to Kornblum [4]. However, the Kornblum oxidation of benzyl bromide I in DMSO in the presence of NaHCO3 (Scheme 1) gave a mixture of aldehyde II and alcohol III at a ratio of ~2 : 1 (cf. [6]). By oxidation of that mixture with pyridinium chlorochromate (PCC) in methylene chloride we succeeded in obtaining aldehyde II in 90% yield. Variation of the reaction conditions made it possible to synthesize alcohol III in 94% yield from compound I, and the subsequent oxidation of III with PCC quantitatively afforded aldehyde II. In addition, benzyl halides can be converted into aldehydes according to Krohnke [5]. The reaction of pyridinium salt IV with N,N-dimethyl-4-nitrosoaniline hydrochloride and subsequent hydrolysis of Schiff ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 7, pp. 1089–1091. © Pleiades Publishing, Ltd., 2013. Original Russian Text © E.B. Nikolaenkova, I.A. Os’kina, V.A. Savel’ev, V.A. Samsonov, A.Ya. Tikhonov, V.A. Ryabinin, A.N. Sinyakov, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 7, pp. 1103–1105.

Solvent-free, one-pot synthesis and biological evaluation of some new dipyrazolo [3,4-b:4′,3′-e]pyranylquinolones and their precursors

One-pot synthesis of 24 new compounds, belonging to three families; dipyrazolo[3,4-b:4′,3′-e]pyranylquinolones 7a–h and its precursors (pyrazolonylidene)methylquinolones 5a–h and 4,4′-[(quinolinyl)methylene]bispyrazols 6a–h, 8 from each, has been achieved in the presence of catalyst tetrabutylammonium hydrogen sulfate (TBA–HS) in solvent-free conditions. In addition to assuring chromatography-free product isolation, this method had also allowed the reaction to proceed in a regio-selective manner provided the temperature and amount of pyrazolone are varied. At 100 °C, while 1:1 mixture of aldehyde 3 and pyrazolone 4 underwent Knoevenagel condensation, same reactants taken in ratio of 1:2 mainly domino/Knoevenagel–Michael reaction. At 120 °C, however, the domino/Knoevenagel–Michael-adducts converted into cyclized product, highlighting a new domino/Knoevenagel–Michael-cyclization synthetic sequence. The structure of all heterocycles has been confirmed by mass, IR and NMR spectral data. Based on 2D NMR NOESY experiment, it was also confirmed that the formation of only ‘Z’ configuration of Knoevenagel alkene took place in the transformation. All are good antitubercular agents as they were found to be active against M. tuberculosis H37RV, in addition to being found active against three Gram-positive (Streptococcus pneumoniae, Clostridium tetani, Bacillus subtilis) and three Gram-negative (Salmonella typhi, Vibrio cholerae, Escherichia coli) bacteria, respectively.

Amberlyst A21 Catalyzed Chromatography-Free Method for Multicomponent Synthesis of Dihydropyrano[2,3-c]pyrazoles in Ethanol

Amberlyst A21 was found to be an extremely efficient catalyst for synthesis of a series of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-carbonitriles by a four-component reaction of a mixture of ethyl acetoacetate, hydrazine hydrate, aldehyde, and malononitrile in ethanol at room temperature. The catalytic efficiency of Amberlyst A21 was compared with some other resin-bound free and anionic bases in order to ascertain the best catalyst for the said conversion. The catalyst was found to work extremely well also for acyclic/cyclic ketones to give corresponding dihydropyrano[2,3-c]pyrazoles or their spirocyclic variants. Easy recovery of the catalyst and its reusability, room temperature reaction conditions, short reaction time, excellent yields, no chromatographic purification, and evasion of environmentally hazardous solvents in the entire reaction process may make this protocol very useful for academia and industry.

Synthesis and reactions of N-acetyl- and N-(2-chloroacetyl)-N-[(2E)-1-methylbut-2-en-1-yl]-2-iodoanilines

The reaction of N-(1-methylbut-2-en-1-yl)-2-iodaniline with Ac2O or ClCH2C(O)Cl results in a mixture of syn- and anti-atropisomers of N-acetyl- and N-chloroacetyl-N-(1-methylbut-2-en-1-yl)-2-iodaniline in a ratio of 1:1. Ozonolysis of the latter followed by reduction with dimethyl sulfide in CH2Cl2 gives rise to the atropisomers mixture of 2-[N-(chloroacetyl)-N-(2-iodophenyl)]aminopropanal in a ratio of 1:3. When heated in boiling benzene, the mixture of atropoisomeric aldehydes reacts with triphenylphosphine to afford a mixture of 2-[(N-acetyl)-N-(2-iodophenyl)]aminopropanal atropisomers in 1:3 ratio.

Repellency, fumigant and contact toxicities of essential oils of selected species from family Myrtaceae against Tribolium castaneum

The uncontrolled use of synthetic chemicals is a great hazard for the environment and consumers. Essential oils were introduced as less toxic agents against mammals and non-targeted insects. In the present study, essential oils from five plant species belonging to family Myrtaceae were extracted using hydro-distillation and their chemical composition was determined by gas chromatography mass spectroscopy. The essential oils were found to be mixtures of hydrocarbons, alcohols, aldehydes and esters. The oils were also assayed for their insecticidal properties against 25 days adult of Tribolium castaneum (red flour beetle). The results showed that the selected essential oils of Eugenia jambolana, Myrtus communis, Melaleuca alternifolia, Melaleuca genistifolia, Sygygium caryophyllatumand Callistemon citrinus had repellency, fumigant and contact toxicities against T. castaneum. The repellency was observed after 24 h. All oils showed repellency at all the applied concentrations. The 100% repellency was shown by M. communis at concentration of 0.000013 ml/ml while S. caryophyllatum, M. alternifolia and C. citrinus showed 100% repellency at 0.0003 ml/ml. In fumigation and contact toxicity bio-assay, the percentage mortality increased with increasing concentration. C. citrinus gave 100% mortality at 0.68ml/ml air at exposure period of 4 h while M. alternifolia, M. communis and E. jambolanashowed 100% mortalities at 0.909 ml/ml air at an exposure period of 4 h. T. castaneum was found highly susceptible to S. caryophyllatum with LC50 value of 0.034 ml/cm2 when exposed to oil for 1 day. While for M. alternifolia, M. communis and M. genistifolia the LC50values were 0.042, 0.060 and 0.533 ml/cm2 respectively at exposure period of 1 day. These investigations showed that the selected essential oils can be used as alternative grain-protectants for stored-products insects. Key words: Aldehydes, bio-assay, environment, hydro-distillation, GC-MS, LC50,mammals, mortality, M. communis, M. genistifolia.

Self-organisation effects in dynamic nanoscale gels self-assembled from simple mixtures of commercially available molecular-scale components

In this paper we report a new, simple gelation system based on an acyl hydrazone building block. These gels can be formed by simple mixing of aldehyde and hydrazide followed by a heat/cool cycle, and constitute a simple type of multi-component gel, in which a new covalent bond is formed. Importantly, we demonstrate two different outcomes when this gelation system is challenged with mixtures of different aldehydes – in some cases, only one of the aldehydes will react with the hydrazide to preferentially form the effective gelator and assemble into organised gels, while in other cases, both aldehydes will react with the hydrazide to yield co-assembled systems. Detailed insight into these assembly processes is obtained through NMR and differential scanning calorimetry. Understanding self-organising systems is a vital step towards the self-assembly of multi-functional advanced materials from complex systems, and also indicates how self-assembly processes, when coupled with chemical reactivity, allow order to spontaneously rise from chaotic mixtures.

Application and characterization of eggshell as a new biodegradable and heterogeneous catalyst in green synthesis of 7,8-dihydro-4H-chromen-5(6H)-ones

An efficient and eco-friendly method for the synthesis of 7,8-dihydro-4H-chromen-5(6H)-ones has been developed by using eggshell as a natural and heterogeneous catalyst. A mixture of an appropriate aldehyde, malononitrile and dimedone in the presence of eggshell at ambient temperature in EtOH resulted in 90–98% yields of the corresponding products. This new and green methodology is of interest due to use of a green, bioactive and biodegradable catalyst, its short reaction time, high yields without further purification and the ability to carry out the large scale reactions. Prepared eggshell was characterized by elemental analysis, infrared spectroscopy, particle size distribution, X-ray diffraction and fluorescence, scanning electron microscope, thermo gravimetric and BET surface area analysis.

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.

Characteristics of TVOC, Aldehydes and Ketones Emitted from Fiber Dryer in Manufacturing of HDF Made from Poplar and Pine

This study, by means of GC-MS and HPLC, investiagted the characteristics of volatile organic compounds (VOCs) released from fiber dryer in a high density fiberboard (HDF) production line with a production capacity of 100,000 m3/a. The quantity of total volatile organic compounds (TVOC), aldehydes and ketones were calculated. The results showed that the concentration of VOCs reached 0.5275 mg/m3. The main components include benzenes series (42.7%), terpenes (11.0% alpha pinene), alkanes (11.2%), anhydrides (4.7%) and aldehydes (3.1%). The concentration of the mixture of aldehydes and ketones was 8.8594 mg/m3. The annual emission of TVOC and the mixture of aldehydes and ketones from HDF fiber dryer were 836 kg/a and 14033 kg/a, respectively.

Investigating the chemical Composition and the antimicrobial activity of the essential oil and Crude Extracts of Sedum Microcarpum (Sm.) schönl Growing Wild in Jordan

Background: Several Sedum species, such as S. album L., S. acre L., S. palaestinum Bieb, and S. pallidum are used in traditional medicine to heal wounds, hemorrhoids, constipation, food fungi, and as laxative and diuretic agents. Materials and Methods: In this study, the antimicrobial activities of the hexane, n-butanol and aqueous methanol extracts as well as the essential oil from Jordanian sedum microcarpum (Sm.) schönl were investigated and Analysis of the oil constituents by using Gas chromatography-Mass spectrometer (GC/MS). Conclusion: The hexane extract showed no antibacterial activity against seven strains. The butanol and aqueous methanol extracts were active against the Gram-positive bacteria Staphylococcus epidermidis, Bacillus cereus and the Gram negative bacteria including Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia and Serratia marcescens. Phytochemical screening of the active extracts revealed the presence of a mixture of quinones, tannins, alkaloids and flavonoids. The essential oil showed moderate activities against the tested strains. Analysis of the oil using Gas chromatography-Mass spectrometer (GC/MS) revealed a complex mixture of aldehydes, mono- and sesquiterpenes in addition to alkaloids. Oxygenated monoterpenes dominated the different classes of compounds detected (36.39%). The major volatile constituents from S. microcarpum included Myrtenol (21.7%), Caryophyllene oxide (8.2%) and z-1, 6-dioldihydromyrcene (5.87%).