Benzaldehyde In Presence Research Articles

A Hypervalent Phosphorane-Palladium Cation Complex Bearing Benzaldehyde

[Rf2PPd(PhCHO)(Ph2PCH2CH2PPh2)] + SbF6-[Rf = o-C6H4C(CF3)20] 5 is prepared by the reaction of Rf2PPdCI(Ph2PCH2CH2PPh2) 1 with AgSbF6 in the presence of benzaldehyde in 92% yield, and the structure determined by X-ray diffraction analysis.

Synthesis of 5-phenyl-10-methyl-7H- pyrimido[4,5-f][1,2,4]triazolo[4,3-a][1,4]diazepine and its evaluation as an anticonvulsant agent

The homolytic benzoylation (benzoyl radical) of 5-tert-butylcarbonylaminopyrimidine (6, 1 equiv.) in the presence of benzaldehyde (3 equiv.), water, sulfuric acid, and acetic acid, upon treatment with FeSO4·7H2O (3 equiv.) and 70% t-BuOOH (3 equiv.) at 5-10°C for 10 min afforded a mixture of 4-benzoyl-5-tert-butylcarbonylaminopyrimidine (7, 23%), 4,6-dibenzoyl-5-tert-butylcarbonylaminopyrimidine (8, 44%), and 4-benzoyl-5-tert-butylcarbonylamino-6- methyl pyrimidine (9, 10%). When a similar reaction was performed using 1 equiv. each of PhCHO, FeSO4·7H2O, and t-BuOOH, to prevent formation of the 4,6-dibenzoyl product 8, the monobenzoyl (7, 38%) and 4-benzoyl-6-methyl (9, 6%) products were obtained. A similar homolytic benzoylation of 5-bromopyrimidine (10) using 1.5 equiv. of reagents to generate the benzoyl radical afforded 4-benzoyl-5-bromopyrimidine (11, 61%) as the predominant product. Elaboration of 11 via a six-step reaction sequence afforded 2-hydrazino-5-phenyl-3H-pyrimido[5,4-e][1,4]diazepine (17) in 5.2% overall yield. The acid-catalyzed reaction of 17 with triethyl orthoacetate gave the title compound 5-phenyl-10-methyl-7H-pyrimido[4,5-f][1,2,4]triazolo[4,3-a][1,4]diazepine (18, 62%). The triazolo compound 18 was more potent than valproic acid (Depakene(r)) in both the subcutaneous metrazol (scMet) and maximal electroshock (MES) anticonvulsant screens, and more potent than clonazepam in the MES anticonvulsant screen but less potent than clonazepam in the scMet anticonvulsant screen.Key words: homolytic benzoylation, pyrimidines, pyrimidodiazepines, anticonvulsants.

Synthesis of 5-phenyl-10-methyl-7<i>H</i>- pyrimido[4,5-<i>f</i>][1,2,4]triazolo[4,3-<i>a</i>][1,4]diazepine and its evaluation as an anticonvulsant agent

The homolytic benzoylation (benzoyl radical) of 5-tert-butylcarbonylaminopyrimidine (6, 1 equiv.) in the presence of benzaldehyde (3 equiv.), water, sulfuric acid, and acetic acid, upon treatment with FeSO4·7H2O (3 equiv.) and 70% t-BuOOH (3 equiv.) at 5-10°C for 10 min afforded a mixture of 4-benzoyl-5-tert-butylcarbonylaminopyrimidine (7, 23%), 4,6-dibenzoyl-5-tert-butylcarbonylaminopyrimidine (8, 44%), and 4-benzoyl-5-tert-butylcarbonylamino-6- methyl pyrimidine (9, 10%). When a similar reaction was performed using 1 equiv. each of PhCHO, FeSO4·7H2O, and t-BuOOH, to prevent formation of the 4,6-dibenzoyl product 8, the monobenzoyl (7, 38%) and 4-benzoyl-6-methyl (9, 6%) products were obtained. A similar homolytic benzoylation of 5-bromopyrimidine (10) using 1.5 equiv. of reagents to generate the benzoyl radical afforded 4-benzoyl-5-bromopyrimidine (11, 61%) as the predominant product. Elaboration of 11 via a six-step reaction sequence afforded 2-hydrazino-5-phenyl-3H-pyrimido[5,4-e][1,4]diazepine (17) in 5.2% overall yield. The acid-catalyzed reaction of 17 with triethyl orthoacetate gave the title compound 5-phenyl-10-methyl-7H-pyrimido[4,5-f][1,2,4]triazolo[4,3-a][1,4]diazepine (18, 62%). The triazolo compound 18 was more potent than valproic acid (Depakene(r)) in both the subcutaneous metrazol (scMet) and maximal electroshock (MES) anticonvulsant screens, and more potent than clonazepam in the MES anticonvulsant screen but less potent than clonazepam in the scMet anticonvulsant screen.Key words: homolytic benzoylation, pyrimidines, pyrimidodiazepines, anticonvulsants.

A Hypervalent Phosphorane–Palladium Cation Complex Bearing Benzaldehyde

[Rf2PPd(PhCHO)(Ph2PCH2CH2PPh2)]+SbF6-[Rf=o-C6H4C(CF3)2O] 5 is prepared by the reaction of Rf2PPdCl(Ph2PCH2CH2PPh2) 1 with AgSbF6 in the presence of benzaldehyde in 92% yield, and the structure determined by X-ray diffraction analysis.

Quantitative Variation in Chemical Defense Within and Among Subgenera of Cicindela

The pygidial secretions of more than 40 species of adult Cicindela were quantitatively assayed by gas chromatography and mass spectrometry for the presence of benzaldehyde, the major defensive compound of cicindelids. All species showed evidence of benzaldehyde secretion, with the range in benzaldehyde spanning three orders of magnitude. Subgenera, species, and subspecies all accounted for a significant portion of the total variation in benzaldehyde secretion, while populations within subspecies sampled at different localities did not vary significantly; thus phylogenetic analyses of benzaldehyde secretion within and among both species and subgenera would be appropriate. The evidence suggests that a single origin of the pathway producing benzaldehyde occurred in the ancestors of Cicindela spp. and that differences among taxa in the amount of benzaldehyde secreted are the result of changes in that pathway's regulation.

Magnesium Oxide-Supported Polytitazane Copper(II) Complex Catalyzed Aerobic Baeyer-Villiger Oxidation of Ketones and Cyclohexanol in the Presence of Benzaldehyde

Magnesium oxide-supported polytitazane copper complex is prepared and found to be a very effective catalyst for the Baeyer-Villiger oxidation of ketones and cyclohexanol in the presence of an aldehyde as a reductant under an atmospheric pressure of oxygen at room temperature. The δ-valerolactone and δ-caprolactone can be obtained in high than 97% yield. The reactivity of ketones decreases as fellow: cycloketones > acetophenone > aliphatic ketone. It is found that cyclohexanol is selectively oxidized to ϵ-caprolactone in 77% yield and 89% selectivity by the above combined catalytic system. The catalyst is also very stable and can be reused at least six times without loss of its activity.

Epoxidation of Oleic Acid in the Presence of Benzaldehyde Using Cobalt(II) Tetraphenylporphyrin as Catalyst

Epoxidation of oleic acid with oxygen in the presence of benzaldehyde using cobalt(II) tetraphenylporphyrin (Co2+-TPP) as catalyst was studied. The results show that high yield of epoxidized oleic acid is obtained by the liquid phase epoxidation of oleic acid in the presence of benzaldehyde using Co2+-TPP as catalyst, which does not catalyze the decomposition of perbenzoic acid, which is one of the oxidation reagents for epoxidation and is formed by the oxidation of benzaldehyde. The oleic acid can be easily epoxidized in this system. The reaction mechanism was proposed. The experimental and theoretical results indicate that the epoxidized oleic acid is formed by a series of free-radical reaction steps. The rate-determining steps were experimentally identified, and the rate equation of epoxidation was obtained. The factors affecting the rate of epoxidation of oleic acid were also obtained.

ChemInform Abstract: Baeyer‐Villiger Oxidation of Cyclohexanone with Molecular Oxygen in the Presence of Benzaldehyde.

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Baeyer-Villiger Oxidation of Cyclohexanone with Molecular Oxygen in the Presence of Benzaldehyde

Abstract The metal-catalyzed Baeyer-Villiger oxidation of cyclohexanone with molecular oxygen (latm) in the presence of benzaldehyde gives δ -caprolactone in high yield. The same oxidation in the absence of metal catalysts is also studied. Additives to the system can improve the reaction highly efficiently.

Photolysis of Aldrin in the Presence of Benzaldehyde in a Solid-Vapor-Air System.

Aldrin (1) was found to undergo epoxidation and isomerization, when irradiated at wavelengths longer than 290nm in the presence of benzaldehyde in air, to give dieldrin (2) and photoaldrin (1,1,2,3,3a,7a-hexachloro-2,3,3a,3b,4,6a,7,7a-octahydro-2,4,7-metheno-1H-cyclopenta[a]pentalene, 3), respectively, followed by isomerization or epoxidation, respectively, to afford photodieldrin (1,1,2,3,3a,7a-hexachloro-5,6-epoxy-decahydro-2,4,7-metheno1H-cyclopenta[a]pentalene, 4) in each case. The predominant photo-products were the epoxides, 2 and 4. These photo-products were also formed when a mixture of 1 and benzaldehyde in air was exposed to sunlight.

Spin trapping chemistry of acyl radicals

AbstractThe EPR spectra of a variety of different acyl radical adducts of PBN (C‐phenyl N‐tert‐butyl nitrone) and MNP (2‐methyl‐2‐nitrosopropane) were measured and their hyperfine splitting constants determined. Included are benzoyl, acetyl and other alkylacyl, alkoxyacyl, aminoacyl and alkylaminoacyl adducts. All examples gave relatively large β‐hydrogen hyperfine splittings ranging from 2.71 to 5.93 G in the PBN spin adducts. Long‐range hyperfine splitting was found to both nitrogen and amino‐hydrogen atoms in the aminoacyl adducts, indicating specific preferred conformations of the spin adducts. The MNP adducts have the well known 7‐8 G nitrogen hyperfine splitting with little else. The existence of hydrogen atom abstraction from benzaldehyde by nitroxides was established, indicating that nitroxides cannot be considered as inert reagents when sent to probe systems containing aldehydes. For example, the EPR signal due to a nitronyl nitroxide was rapidly quenched in the presence of benzaldehyde in benzene. Also, a surprising increase in intensity of benzoyl PBN adduct was noted after photolysis when the light was turned off. Double acyl adduct formation is proposed.

Selective synthesis of monoaryl substituted porphyrins

AbstractA synthetic route to meso‐monoarylporphyrins using a MacDonald‐type 2 + 2 condensation is described. In this method a bisformyl substituted dipyrrylmethane is treated with a biscarboxydipyrrylmethane. The 5‐aryldipyrrylmethanes 15, 25 and 27 were obtained by condensation of the corresponding pyrroles 18, 28 and 29 respectively with benzaldehyde in presence of p‐toluenesulfonic acid.

Intrinsic cellular resistance to oxazaphosphorines exhibited by a human colon carcinoma cell line expressing relatively large amounts of a class-3 aldehyde dehydrogenase

A cultured human colon carcinoma cell line, viz. colon C, exhibiting intrinsic cellular resistance to mafosfamide mediated by relatively elevated levels of a cytosolic class-3 aldehyde dehydrogenase was identified. Colon C cells were found to be much less sensitive/more resistant (about 10-fold as judged by lc 90 values) to mafosfamide than were two other cultured human colon carcinoma cell lines, viz. RCA and HCT 116b, and, as compared to the barely detectable dehydrogenase activity (NADP-dependent enzyme-catalyzed oxidation of benzaldehyde to benzoic acid) in RCA and HCT 116b cells, that in colon C cells was about 200-fold greater. The three cell lines were equisensitive to phosphoramide mustard. Aldehyde dehydrogenase activity was confined to the cytosol in colon C cells (as well as in the other two cell lines) and, on the basis of its physical, immunological and catalytic characteristics, the operative enzyme was judged to be a Type-1 ALDH-3 identical to the Type-1 ALDH-3 expressed in methylcholanthrene-treated human breast adenocarcinoma MCF-7/0 cells and very nearly identical to the Type-1 ALDH-3 expressed in human normal stomach mucosa. Class-1 and class-2 aldehyde dehydrogenases were not found in these cells. The relative insensitivity to mafosfamide on the part of colon C cells was not observed when exposure to mafosfamide was in the presence of benzaldehyde or 4-(diethylamino)benzaldehyde, each a relatively good substrate for ALDH-3, whereas it was retained when exposure to mafosfamide was in the presence of acetaldehyde, a relatively poor substrate for this enzyme. Sensitivity to mafosfamide on the part of HCT 116b and RCA cells, and to phosphoramide mustard on the part of all three cell lines, was unaffected when drug exposure was in the presence of any of the three aldehydes. Together with earlier reports from our laboratory, these observations demonstrate that intrinsic, as well as stable and transient acquired, resistance to oxazaphosphorines, such as mafosfamide and cyclophosphamide, can be mediated by relatively increased levels of cytosolic class-3 aldehyde dehydrogenases.

The Burning of Incense as an Indoor Source of Volatile Organic Compounds

Incense burning in indoor environments is a common practice in many coun tries and communities in the world. In the present investigation one type of incense was used for the purpose of studying the quality and quantity of emis sions released, both before and during burning with respect to volatile organic compounds including aldehydes. The polycyclic aromatic hydrocarbon (PAH) content and elemenal composition of air particulate matter and ash were also investigated. The study included controlled experiments in an environmental chamber as well as field tests. The results showed the presence of benzalde hyde, linalool, benzyl alcohol, phenethyl alcohol, formaldehyde, and acetalde hyde in the emissions of incense both before and after burning. Incense burn ing produced additional compounds, such as benzene, toluene, and diethyl phthalate. The concentrations of these compounds depended on the time of sampling. No PAHs were detected in air particulate matter after incense burn ing or in the combustion residue...

Two-photon chemistry in the laser jet: generation of radical intermidiates and their photochemical transformations

Abstract The novel laser jet technique provides sufficiently high photon densities to permit the observation of the photochemistry of photochemically generated radicals (two-photon chemistry) in the liquid phase. Four recent applications of this novel photochemically useful method are presented: these include the photochemistry of hydroxydiphenylmethyl, 9-hydroxyxanthenyl, diphenylmethyl, and benzoyl radicals under laser jet and normal photolysis conditions. The regioselectivity of cross-coupling reactions of hydroxydiphenylmethyl or 9-hydroxyxanthenyl radicals with solvent-derived radicals changes when these species are electronically excited, i.e. under the high intensity conditions of the laser jet, cross-coupling at the para position (head-to-tail combination) is significantly enhanced relative to the normal coupling mode at the hydroxy-bearing radical site (head-to-head combination). Semiempirical calculations of the spin density distributions for the ground and first excited states of the radicals confirm the change in spin density from the hydroxy-bearing carbon atom to the conjugating benzene rings in these radical species on photoexcitation. For the diphenylmethyl radical, two reaction pathways have been observed under the high photon densities of the laser jet: the electronically excited diphenylmethyl radical can either abstract a chlorine atom from carbon tetrachloride through an electron transfer process or can be photoionized on further photoexcitation (multiphoton chemistry). The resulting benzhydryl cation was trapped by methanol as the corresponding ether product, which unequivocally demonstrates that carbene formation by photoejection of a hydrogen atom does not take place under laser jet photolysis conditions. An advantage of the high photon densities produced in laser jet photolysis is the high steady state concentration of short-lived transients that are generated, which enable unprecedented intermolecular reactions to be observed. Thus, about a millimolar concentration of tert -butoxy radicals can be obtained in the laser jet photocleavage of tert -butyl peroxide. When the tert -butoxy radicals are produced in the presence of benzaldehyde, the main product is tert -butyl benzoate. If carbon tetrachloride is also present, chlorobenzene can be detected. This is rationalized as the product derived from chlorine abstraction by phenyl radicals, which are presumably produced by the photodecarbonylation of benzoyl radicals. An alternative method of obtaining benzoyl radicals is the two-photon cleavage of benzil. The laser jet photolysis of benzil in tert -butyl peroxide yields mainly tert -butyl benzoate, whereas in carbon tetrachloride, benzoyl chloride, chlorobenzene and α,α,α-trichloroacetophenone are observed. The first two products result from chlorine atom abstraction by the photochemically generated benzoyl and phenyl radicals, and the last product from in-cage cross-coupling between benzoyl and trichloromethyl radicals. Such product studies provide detailed mechanistic information on the photochemical behaviour of electronically excited, short-lived transients which complements nicely the kinetic and spectral data of time-resolved laser flash studies. Consequently, the laser jet technique constitutes a valuable tool for determining the mechanism of two- photon reactions.

Benzil-benzilic acid rearrangement in crosslinked macromolecular systems: effect of crosslinking

The effect of the molecular character and extent of crosslinking units on polymer-analogous benzil-benzilic acid rearrangement was investigated. A typical hydrophobic styrene-divinylbenzene copolymer and a hydrophilic styrene-tetraethyleneglycol diacrylate copolymer were used as the polymer supports. Supports with crosslink densities varying from 2 to 20% were functionalized. The polymer-bound aldehydes were subjected to crossed benzoin condensation in the presence of benzaldehyde. The benzoin analogues were converted to benzils and then subjected to benzil-benzilic acid rearrangement. The products were characterized by i.r. and 13C n.m.r. spectroscopy and the extent of rearrangement was determined by chemical methods.

Transition-metal-catalyzed decomposition of diazo(trialkylsilyl)-acetates: Intermolecular formation and trapping of carbonyl ylides

Transition-metal-catalyzed decomposition of diazoesters 2 in the presence of benzaldehyde, crotonaldehyde, or acetaldehyde generates carbonyl ylides which can be trapped with dimethyl fumarate. dimethyl maleate, and dimethyl acetylenedicarboxylate to give tetrahydrofurans 4,6,7, and 8 and dihydrofuran 10, respectively. Decomposition of 2a in the presence of benzaldehyde and methyl cyanoformate affords no products derived from a carbonyl ylide, but rather the oxazole 12. X-ray crystal structures of 4a and 6 are provided.

Sorption and diffusion of aldehydes and ketones into elastomers

AbstractThe results of the sorption and diffusion of aldehydes and ketones into structurally different elastomers such as ethylene propylene diene terpolymer, styrene butadiene rubber, nitrile butadiene rubber, neoprene and natural rubber are described in the temperature interval of 25‐60°C. From these data, the Arrhenius parameters for the processes of diffusion and permeation are determined. The activation parameters for the diffusion of ketones range from 10.29 to 49.62 kJ/mol and for aldehydes, from 13.18 to 50.42 kJ/mol; these values fall in the range expected for rubbery polymers well above their glass transition temperatures. Transport data are affected by the nature of the interacting solvent molecule rather than its size and also by the structural variations of the elastomers. For all the solvents, the polymers remained intact; however, natural rubber in the presence of benzaldehyde showed degradative reactions at higher temperatures. Volumetric expansions of the elastomers have been measured from the dimensional response in the presence of aggressive solvents.

Production of L‐phenylacetyl carbinol by immobilized yeast cells: I. Batch fermentation

Immobilization of Saccharomyces cerevisiae ATCC 834 within alginate beads enhances microbiological conversion of benzaldehyde to L-phenylacetyl carbinol (L-PAC), a precursor employed for synthesis of L-ephedrine. Yields of 90% L-PAC on benzaldehyde (initially 0.6% in medium) were obtained with immobilized cells, in contrast to about 10% with free cells which tend to form pellets in the presence of benzaldehyde. The predominant favorable action of immobilization appears to be a reduction in the toxic or inhibitory effects of benzaldehyde. With an initial benzaldehyde concentration of about 0.6% in the medium the optimum cell mass concentration was observed to be about 28 g cell mass (immobilized) per liter of medium.

Cluster Chemistry. Catalytic Behavior of [H2Ru4(CO)12]2− in Reduction of Benzaldehyde and Nitrobenzene

Abstract The dianion, [H2Ru4(CO)12]2−, showed excellent catalytic activity for the reduction of nitrobenzene, but not of benzaldehyde. In the presence of benzaldehyde under H2 pressure, the dianion was converted to a new species of good catalytic activity, which is closely similar to a complex obtained from the reaction of [H2Ru6(CO)18] with DBU (1,8-diazabicyclo[5.4.0]undec-7-ene).