Formation Of Aromatic Compounds Research Articles

Formation of Aromatic Compounds from Carbohydrates. VII. Reaction of D-Glucose and Glycine in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. VII. Reaction of D-Glucose and Glycine in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. V. Reaction of D-Glucose and Methylamine in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. V. Reaction of D-Glucose and Methylamine in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. Part III. Reaction of D-Glucose and D-Fructose in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. Part III. Reaction of D-Glucose and D-Fructose in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. IV. Chromones from Reaction of Hexuronic Acids in Slightly Acidic, Aqueous Solution.

Formation of Aromatic Compounds from Carbohydrates. IV. Chromones from Reaction of Hexuronic Acids in Slightly Acidic, Aqueous Solution.

Studies of Structural Changes of Unsaturated Fatty Acid by Heating

When polyunsaturated fatty acids are heated, cyclization occurs as well as decomposition and polymerization. J.A. MacDonald, R.B. Hutchson and J.C. Alexander et al. have reported that cyclic monomers from heated linseed oil contain cyclohexadiene compounds. N. Matsuo informed the presence of cyclohexadiene compounds as main components and ortho-substituted aromatic compounds in heated ethyl β-eleostearate.One double bond in polyunsaturated straight chain monomer disappears in intramolecular cyclization as a matter of course. But it is very interesting that aromatic compounds are present in the heated trienoic acid.In this paper, cyclic monomers were prepared from linseed oil under the condition of 295°C, 15min. in stainless autoclave with alkaline catalyst. Heated linseed oil fatty acid sodium salt was acidified and methyl esterified by the usual method, thus cyclic monomers were obtained by urea adduct separation. Nextly, the cyclic monomers were heated in 25ml ampoules under various conditions. These samples were analyzed by GLC, IR, and colorimetry of cyclohexadiene ring, etc.As a result, cyclohexadiene compounds gradually decreased, with inverse increase in the aromatic and cyclohexene compounds. The mechanism of formation of aromatic compounds in the cyclic monomers was explained by disproportionation reaction.

Formation of Aromatic Compounds from Carbohydrates : Part 1. Reaction of d-glucuronic Acid, d-glacturonic Acid, d-xylose, and l-arabinose in slightly acidic, aqueous solution

The reaction of d-glucuronic acid in aqueous solutions of pH 3.5 and 4.5 at 96° yielded 2-furaidehyde ( 1), 2-furoic acid ( 12), 2,3-dihydroxy-2-cyclopentcn-l -one (reductic acid) ( 2), 1,2-dihydroxybenzene ( 7), 1,2,3-trihydroxybenzene ( 8), 2,3-dihydroxytoluene ( 10), 2,3-dihydroxybenzoic acid ( 9), 2,3-dihydroxyacetophenone ( 11), 3,8-dihydroxy-2-methylchromo.le ( 3), 5,6,7,8-tetrahydro-3,5-dihydroxy-2-methyl-8oxobenzopyrone ( 4), and 3-acetyl-l-oxocyclohexane-2,3,6-trioI ( 18). The last two compounds were shown to be precursors of 3 and 11, respectively. Two compounds of formula C 10H 8O 5, ( 5, bd6) were also isolated. From the reaction of d-galacturonic acid at pH 4.5, most of the above compounds were isolated, but in lower yields, and from d-xylose, compounds 1,3,4,6, 10, 11, and C 10H 8O 4 were obtained. l-Arabinose yielded the same main components as d-xylose (except for the absence of 6) but in lower yields.*Dedicated to Professor M. Stacey, C.B.E., F.R.S., in honour of his 65th birthday.

Formation of aromatic compounds from D-glucuronic acid and D-xylose under slightly acidic conditions

1,2-Dihydroxybenzene, 2,3-dihydroxytoluene, 2,3-dihydroxybenzoic acid, 2,3-hydroxyacetophenone, 3,8-dihydroxy-2-methylchromone (I), and its precursor 6,7,8,8a-tetrahydro-3,8a-dihydroxy-2-methyl-8-oxobenzopyrone (II) were obtained by reaction of D-glucuronic acid in slightly acidic aqueous solution (the last three products also from D-xylose).

Pyrogenesis of Aromatic Hydrocarbons Present in Cigarette Smoke II: Pyrolytic Products of some Representative Constituents of the Hexane Soluble Fraction of Tobacco

Abstract In continued studies to reevaluate the contribution of the hexane-soluble fraction of flue-cured tobacco to the formation of aromatic compounds, especially polynuclear aromatic hydrocarbons, present in cigarette smoke, some compounds representative of that fraction have been pyrolyzed (860°C, N2). The straight chain saturated compounds, n-hexane, stearic acid, and dotriacontane, produced pyrolysates distinguished by relatively low yields of total neutrals and the absence of any significant quantities of aromatic products with alkyl side chains. Compounds containing double bonds, such as the unsaturated fatty acid, linolenic acid and its methyl ester, and the polyene squalene, which like phytol is also characterized by methyl groups on the chain, produced relatively higher yields of neutral products, including alkyl-substituted aromatic hydrocarbons. Phytol, of course, also exhibited this tendency. Pyrolysis of the plant sterol, b-sitosterol, produced the greatest amounts of phenanthrene and BaP. Estimates of BaP levels in pyrolysates indicate that phytol, in addition to the above mentioned sterol, is a relatively effective high temperature precursor of this important carcinogen. The hexane solubles of flue-cured tobacco were shown to produce BaP in levels intermediate to the least effective (stearic acid) and most effective (b-sitosterol) precursor examined.

Composition Studies on Tobacco. XXlll: Pyrolytic and Structural Investigations on the Polyphenol-amino Acid Pigments of Leaf

AbstractThe complex polyphenolic pigments of Turkish tobacco have been pyrolyzed to determine their possible contribution to the formation of aromatic compounds, especially polynuclear aromatic hydrocarbons (PAH), of smoke. The dark brown pigments were initially obtained by a basic aqueous extraction of tobacco. Various hydrolytic procedures showed the presence of rutin, chlorogenic acid, and a series of amino acids; some information on the structure of these pigments is presented. The pyrolysis of the pigments was carried out at 850°C and the products were fractionated to reveal the presence of more than a dozen PAH. Addition of pigments to cigarettes gave an increase in the level of benzo[a]pyrene in the smoke. The possible role of the polyphenolic pigments as a source of PAH in smoke is discussed

Synthetic reactions of dimethylformamide. XXI. The formation of aromatic compounds during the formylation reactions

Synthetic reactions of dimethylformamide. XXI. The formation of aromatic compounds during the formylation reactions

852. Studies in relation to biosynthesis. Part XXIII. The formation of aromatic compounds from β-polyketones

852. Studies in relation to biosynthesis. Part XXIII. The formation of aromatic compounds from β-polyketones

Nitrogenous Constituents of Some Paleozoic Shales: ABSTRACT

As much as three-quarters of the nitrogen in some Paleozoic shales was released as ammonia by acid hydrolysis; from 1 to 5 per cent as amino acids. The nitrogen released as ammonia occurred largely as ammonium ions held within the octahedral pores making up the crystalline nuclei of illite clay minerals. The presence of nitrogenous organic constituents within the characteristic expansible layers of silicate minerals was also indicated. The organic matter adsorbed on the internal surfaces of the clay was non-extractable with alkali, but was removed readily through decomposition of the clay with hydrofluoric acid. A comparison of the organic constituents in shales with those in recent sediments showed that a smaller fraction of the organic matter in shales occurred in protein derivatives. The carbon-organic nitrogen ratio in shales was higher than in recent deposits. The suggestion is made that the transformation of complex organic materials in marine muds consists, in part, of the formation of aromatic compounds from sugar-amine condensation products, and that, concomitantly, nitrogen is lost as ammonia and petroleum constituents are formed. End_of_Article - Last_Page 1257------------