Showing papers on "Benzaldehyde published in 1977"

Stereo-ordered macromolecular matrices bearing ammonium groups as catalysts in alkylation and carbenation reactions

Abstract: Selective alkylation of benzyl cyanide and dichlorocarbenation of styrene and benzaldehyde are promoted by macromolecular ammonium salts under polyphase conditions.

Base-catalysed Neber-type rearrangement of glucosinolates [1-(β-D-glucosylthio)-N-(sulphonato-oxy)alkylideneamines]

Abstract: Allylglucosinolate in aqueous base produces vinylglycine (2-aminobut-3-enoic acid), thioglucose, and sulphate by a reaction of the first order with regard to both glucosinolate and hydroxide ion. No deuterium is introduced at C-2 of the amino-acid when the reaction is performed in D2O. The reaction presumably takes place through a Neber-type rearrangement, starting with concerted loss of a hydrogen atom at C-2 in the aglucone, bond formation between C-2 and the nitrogen atom, and loss of sulphate, followed by fast addition of water to the resulting azirine, ring opening of the hydroxyaziridine produced, and finally hydrolysis of the thioester thus obtained. Benzylglucosinolate correspondingly yields phenylglycine, thioglucose, and sulphate in aqueous base but in this case other products, including benzaldehyde, benzyl cyanide, cyanide, and thiocyanate, are observed. Both vinylglycine and phenylglycine are produced in partly racemised forms but with an excess of the L-isomer. The reaction of the glucosinolates is facilitated by a high kinetic acidity of the hydrogens at C-2 in the aglucone, but glucosinolates other than the allyl and benzyl compounds can also give α-amino-acids with aqueous base, although only at elevated temperature.

Reduction of carbonyl compounds by sodium borohydride (tetrahydridoborate) in water, dimethyl sulphoxide, and their mixtures as solvents: products and kinetics

Abstract: Rate measurements are reported for the reduction of acetone pivalaldehyde, and benzaldehyde by sodium and tetramethylammonium tetrahydridoborates in dimethyl–sulphoxide–water systems, some containing a low concentration of sodium hydroxide to impede the hydrolysis of tetrahydridoborate. The reactions obey second-order kinetics. The rate constants decrease as the water content of the solvent is reduced but, with the most reactive substrate (benzaldehyde), the reduction is still detectable even in a solvent not containing any added water. Evidence has been obtained that the reduction product of benzaldehyde in dimethyl sulphoxide solution is sodium tetrakisbenzyloxyborate, which is readily hydrolysed to benzyl alcohol. A condensation product of benzaldehyde and dimethyl sulphoxide (2-methylsulphinyl-1-phenylethanol) has been isolated as a by-product. Attempts to trap borane during the reduction gave negative results.

Catalytic gas phase oxidation of toluene to benzaldehyde and/or benzoic acid

Abstract: A catalyst mass of silver vanadate and iron vanadate, optionally also including at least one rare earth metal vanadate, is used in the vapor phase oxidative conversion of toluene to benzaldehyde and/or benzoic acid using oxygen or ozone and steam according to the disclosed process. Catalyst activity and selectivity are improved.

Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

Abstract: Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence Such complexes are useful in the assay of enzymes

Synthesis and Properties of Cobalt(II), Nickel(II), and Copper(II) Complexes with Acetaldehyde Oxime and Benzaldehyde Oxime

Abstract: Cobalt(II), nickel(II), and copper(II) complexes with acetaldehyde oxime and benzaldehyde oxime have been prepared and characterized by vibrational and electronic spectroscopy, magnetism, and other methods. The cobalt(II) and nickel(II) complexes isolated are of the general formulae: (A) MX2(oxime)4 (X=Cl, Br, I, NO3, NCS and CH3COO); (B) M(NCS)2(oxime)2; (C) MSO4 (oxime)3·3H2O. They are all six-coordinate, and the complexes (B) are probably multinuclear. Copper(II) forms complexes of the formulae: (A) CuX2(oxime)4 (X=Cl, Br), (B) CuX2(oxime)2 (X=Cl, Br, NCS); (C) CuSO4(oxime)H4·H2O. Possible structures for these copper(II) complexes are also discussed. Acetaldehyde oxime and benzaldehyde oxime are unidentates in all these complexes, being coordinated through their nitrogen atom.

Metabolism of mandelic acid by Neurospora crassa.

Abstract: Preliminary studies on the metabolism of mandelic acid by Neurospora crassa reveal the operation of a pathway for its degradation which involves benzoyl formic acid, benzaldehyde, benzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid as the intermediates. This pathway is different from that followed by bacterial systems and is the same as that observed in Aspergillus niger.

N-oxides and related compounds. Part 58. Some precursors of pyridinium methylide

Abstract: 1-t-Butoxycarbonylmethylpyridinium ion (3) is pyrolysed to yield successively the 1-carboxymethyl- and the 1-methyl-pyridinium ions. The intermediate ylide (1) could be trapped by benzaldehyde and other electrophiles.1-Carboxymethylpyridinium betaine (5) reacts with aldehydes as the ylide tautomer (6) to give products (8) of aldol reactions, transformations of which are described. The reactions of various other electrophiles with the betaine (5) have been investigated.The ylide (20) from the cation (3) reacts as expected with methyl iodide, benzyl bromide, and benzoyl chloride (at 0 °C). At 25 °C, benzoyl chloride gives a product of further acylation, as do other acid halides.

Hydroxylamin—Hydroxynitron-Gleichgewichte

Abstract: From the hydroxylaminomethylation product of 2-naphthol (3) and aliphatic resp. aromatic aldehydes resulting compounds were examined by NMR spectroscopy. In solution the products of formaldehyde, acetaldehyde and benzaldehyde show equilibria of cyclic hydroxylamine and hydroxynitrone forms2 resp.1, the state of which depends on the solvent; with the derivatives of p-nitro- and p-dimethylaminobenzaldehyde only the hydroxynitrone form1 d resp.1 e is detectable.

Process for the purification of benzoic acid

Abstract: A process for purifying benzoic acid, especially benzoic acid obtained by the catalytic oxidation of toluene in the liquid phase which can be contaminated with impurities such as diphenyl, methyldiphenyl, a phenyl-benzoic acid, benzaldehyde, benzyl benzoate, succinic anhydride, phthalic anhydride, formic acid or formaldehyde, by contacting the benzoic acid with an amine of the formula Hsub2 N -- R wherein R is hydrogen, a straight or branched chain alkyl radical of 1 to 4 carbon atoms or a cycloalkyl radical of 5 or 6 carbon atoms or a salt thereof and benzoic acid is distilled off or sublimed from the resultant reaction mixture The benzoic acid so obtained can be reacted with sodium hydroxide solution and highly pure sodium benzoate can be removed by extraction with toluene or steam distillation

Anodic oxidn. of toluene and xylene(s) - to produce methyl benzyl ether(s) and methoxy benzaldehyde(s)

Abstract: The reaction is carried out using a Pt anode in a bath comprising the methyl benzene cpd., methanol, an inert solvent selected from halogenoalkanes and satd. aliphatic nitriles and, as electrolyte support, sulphuric acid or sulphonic acids and their salts with tert. amines and opt. water. In the case of toluene oxidn., methyl benzyl ether is used to produce benzyl alcohol and p-aminoaldehyde is used in perfumes and as a flavouring. The process gives economic yields compared with previous processes.

Gas and Solution Phase Reactivities of Triplet Aromatic Carbonyls

Abstract: Absolute rate studies pertinent to the gas and solution phase photochemistry of triplet benzaldehyde, acetophenone and benzophenone have been carried out, and it has been confirmed that, in the gas phase, attack on a hydrocarbon by the carbonyl results in the expected hydrogen abstraction. Also absolute rates in both the gas phase and solution (acetonitrile) are quite comparable. For a given carbonyl the differences in the rates of abstraction are largely accounted for by activation energy changes. The activation energies vary from a high of 4.8 kcal mol−1 for abstraction of a primary hydrogen by acetophenone to a low of 1.4 kcal mol−1 for abstraction of tertiary hydrogen by benzaldehyde. At room temperature the relative reactivities of primary, secondary and tertiary C—H bonds for all the carbonyls are 1:23:190. In solution benzophenone is two times more reactive than acetophenone, while benzaldehyde is ten times more reactive. In the gas phase benzaldehyde is about 18 times more reactive than acetophenone. Molecular orbital calculations indicate that the greater reactivity of benzaldehyde as compared to acetophenone stems from steric hindrance in the latter. The quenching of acetophenone triplets by various other substrates including naphthalene, benzene, isopropanol and triethylamine is also discussed.

Novel schiff bases

Abstract: A process is described for isomerizing the cis,cis- and cis,trans-isomers of di-(p-aminocyclohexyl)methane to the corresponding trans,trans-isomer. The starting isomer, or mixture of isomers, is converted to the corresponding bis-benzaldimine by reaction with benzaldehyde (or benzaldehyde containing 1 to 3 inert substituents), the bis-benzaldimine is isomerized in the presence of a basic catalyst (potassium t-butoxide, potassium hydroxide preferred) to give predominantly the trans,trans-isomer of the bis-benzaldimine, and the latter is subjected to acid hydrolysis to yield the trans,trans-isomer of the free diamine. The process can be applied to the individual cis,cis- and cis,trans-isomers of the diamine as well as to admixtures of these isomers with the trans,trans-isomer, such as the mixtures of these stereo-isomers obtained by catalytic hydrogenation of di-(p-aminophenyl)methane.

Some mechanistic studies on the hydrolysis of acetals and hemiacetals

Abstract: The general-acid catalysed hydrolysis of acetals is discussed. It is shown that under certain conditions the rate-limiting step in the hydrolysis of α-acetoxy-α-methoxy-toluene and benzaldehyde di-t-butylacetal is decomposition of the hemiacetal. Attempts to study the decomposition of tetrahedral intermediates at the oxidation level of carboxylic acids are described.

Kinetics of ozonation of aldehydes in relation to their ozone-initiated autoxidation

Abstract: The rates of ozonation of aliphatic aldehydes and monosubstituted benzaldehydes are measured in carbon tetrachloride solutions, and the reaction order and the rate constants are determined on the basis of the theory of gas absorption accompanied by chemical reactions. It is found that the reaction is first order with respect to both ozone and benzaldehyde, and also that the second order rate constants for n- and iso-butyraldehydes are much higher than those for the substituted benzaldehydes studied. The order of reactivity of substituted benzaldehydes is anisaldehyde> p-tolualdehyde> benzaldehyde> p- and m-chlorobenzaldehydes> p- and m-nitrobenzaldehydes. It is also found that the rate of ozonation of substituted benzaldehyde follows Hammett''s rule. Furthermore, the kinetics of liquid-phase autoxidation of benzaldehyde with ozone-oxygen mixture is studied, and the observed oxidation rates are found to be approximately consistent with those predicted on the assumption that the reaction of ozone with aldehyde is an initiation reaction of the autoxidation.

Elektrocyclische Synthese von aromatischen Aldehyden aus kettenförmigen Polymethinfarbstoffen

Abstract: Aus kettenformigen Heptamethinfarbstoffen bildet sich in einer elektrocyclischen Reaktion Benzaldehyd, aus Nonamethinen entsprechend Zimtaldehyd. Die Ausbeuten der Reaktion in Abhangigkeit von der Wasserstoffionenkonzentration und die Eyring-Parameter werden bestimmt. Electrocyclic Synthesis of Aromatic Aldehydes from Chain-shaped Polymethine Dyes Chain-shaped heptamethines form benzaldehyde by an electrocyclic reaction whereas nonamethines give cinnamic aldehyde. The Eyring parameters and the yields of the reaction are determined in dependence on the concentration of hydrogen ions.

Preparation of α-cyanobenzyl esters

Abstract: New α-halobenzyl esters, intermediates for α-cyanobenzyl pyrethroid esters, are prepared by treating a benzaldehyde derivative with a pyrethroid acid halide. The resulting α-halobenzyl ester is treated with a water-soluble compound capable of generating cyanide ions (CN - ) to give the corresponding α-cyanobenzyl esters.

Oxidation of Cinnamyl Alcohol with Peracetic Acid in Acidic Solvents

Abstract: Peracetic acid oxidation of cinnamyl alcohol(1) in tetrahydrofuran(THF) at room temperature has been found to give phenylacetic acid(2), benzaldehyde(4) and cinnamyl acetate(5) as major products. A probable first-formed intermediate, 2,3-epoxy-3-phenyl-1-propanol(7), was detected as its derivative (1-phenyl-1,2,3-propanetriol), and also a probable second intermediate, 1-hydroxy-3-phenyl-2-propanone (3), was detected. 3 was found to be converted to 2 by the Baeyer-Villiger reaction. On the other hand, the peracetic acid oxidation of 1 in methanol gave a methanolysis product of oxirane ring, 3-methoxy-3-phenyl-1,2-propanediol(6a), a small amount of a rearrangement product and benzaldehyde. The peracid oxidation of 1 in various solvents was also studied. A probable reaction mechanism is discussed.

Phenyloxazoline derivatives of amino-sugars. Part 3. Preparation of intermediates for the synthesis of sphingoglycolipids.

Abstract: 1,2-Dideoxy-5,6-O-isopropylidene-2′-phenyl-α-D-glucofuranoso[2,1-d]-Δ2′-oxazoline (1) was readily converted into allyl 2-benzamido-2-deoxy-5,6-O-isopropylidene-βD-glucofuranoside (4) by the action of the pyridine salt of toluene-p-sulphonic acid in allyl alcohol–pyridine at reflux. This method is superior to acid alcoholysis for the conversion. The mesylate of the alcohol (4) was converted into allyl 2,3-dideoxy-5,6-O-isopropylidene-2′-phenyl-β-D-allofuranosido[2,3-d]-Δ2′-oxazoline (9) by hot aqueous triethylamine. The isopropylidene group of compound (9) was hydrolysed preferentially in anhydrous methanol and the allo-diol (12) produced was converted into the talo-anhydride (17), which was hydrolysed to give the talo-diol (18). The allo-diol and the talo-anhydride are potential intermediates for the synthesis of sphingosine. The isomerisation of the allyl group of compound (9) to a prop-1-enyl group, without affecting the phenyloxazoline group, was accomplished by the action of commercial potassium t-butoxide in dimethyl sulphoxide containing t-butyl alcohol or preferably by the action of chloro(tristriphenylphosphine) rhodium (I).The action of acidic benzyl alcohol, containing benzaldehyde, on 3-O-benzyl-1,2-dideoxy-5,6-O-isopropylidene-2′-phenyl-α-D-glucofuranoso[2,1-d]-Δ2′-oxazoline (2) at 20 °C led to the separation of the highly crystalline (m.p. 300°) benzyl 2-benzamido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-β-D-glucopyranoside (30) in high yield from the reaction mixture. This compound was converted, by two routes involving allyl ethers, into benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside (40), an intermediate required for the synthesis of the immunological determinant of the P′-antigen. The conversion of benzamido- into acetamido-groups was accomplished with acetic anhydride–acetic acid containing sodium acetate at reflux. It was shown that allyl ethers and O-benzylidene groups were stable to the conditions of this conversion. Benzyl 2-acetamido-6-O-allyl-3-O-benzyl-2-deoxy-β-D-glucopyranoside (48) was also prepared.

Synthesis of Nitriles from Aldehyde Oximes Using Trivalent Phosphorus Compounds

Abstract: Aldehyde oximes reacted with phosphorous tris (diethylamide) P (NEt2) 3 under reflux in THF, giving the corresponding nitriles in good yield. Reaction of benzaldehyde oximes with some trivalent phosphorus compounds was also examined.

Process for the purification of a phenol

Abstract: A process for the purification of a phenol compound prepared by decarboxylative oxidation of a benzoic acid to a phenol compound, including treating the phenol with a countercurrent flow of phosphoric acid and a temperature gradient to remove substituted and unsubstituted benzaldehyde and related compounds.