Oxidation von Polyisopren-Popcorn-Polymerem. 5. Mitt. Raman-Spektren von Polyisopren-Popcorn Polymerem im Laufe der Oxidation

Ohne Zusammenfassung     

Oxidation reactions of azines.

Condensation of 2-([2.2]paracyclophan-4-yl)propene with formaldehyde and amines gave 4-paracyclophanyl substituted -piperidols which were readily dehydrated to the corresponding tetrahydropyridines. N-Methyl substituted 4-paracyclophanyltetrahydropyridine has been oxidized to the corresponding piperidin-2-one.For communication 2, see [1]. This article is also communication 4 in the series Synthesis, structure and biological activity of [2.2]paracyclophanes (for communication 3, see [2]).Russian University of National Friendship, Moscow 117198. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 653–658, May, 1997,     

Oxidation of Polyisoprene Popcorn Polymer. V. Raman Spectra of Polyisoprene Popcorn Polymer Following Oxidation

From Raman spectral data, no decrease in the double-bond content of polyisoprene popcorn polymer was detected following various periods of oxidation. No conclusion could be made concerning the fate of the 1,2 or 3,4 vinyl-group attachments.     

Oxidation with permanganate in strong alkaline medium. Oxidation of pyruvic and lactic acids

The reaction of permanganate ion with pyruvic acid and lactic acid has been studied in aqueous solutions containing 0.10–2.0 mol dm^?3 alkali. In this range of HO^? concentration the reaction is followed slowly by the reduction of manganate, thus, the above process can be studied separately. In the case of lactic acid (LA), the reactive species is alkoxy anion, and the deprotonation constant could be calculated from the kinetic data. A mechanism based on electron abstraction from the alkoxy anion has been proposed. In the case of pyruvic acid (PA) oxidation may proceed with participation of enolate anion, or hydrate anion, or an adduct. These three possibilities have been investigated. © John Wiley & Sons, Inc.     

Oxidation of 3-hydroxykynurenine. A reexamination

The oxidation mixture of 3-hydroxykynurenine ( 1 ), treated with aqueous acetic anhydride and, subsequently, with acidic methanol, yields the 1-hydroxy-3-carbomethoxy-5-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine ( 5 ), the 1-hydroxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5.H-pyrido[3,2-a]-phenoxazin-5-one ( 6 ), the 1-methoxy-11-(β-aspartoyl-N-acetyl-methyl ester)-5H-pyrido[3,2-a]phenoxazin-5-one ( 6a ), the l,5-dimethoxy-11-(β-aspartoyl-N-acetyl-methyl ester)pyrido[3,2-a]phenoxazine ( 7 ) and the 1-methyl-1(1′-[11-(β-aspartoyl-methyl esterimino)]ethenyl)ketal-1H,5H-pyrido[3,2-a]phenoxazin-5-one ( 8 ). A probable scheme, for the compound formation, is reported.     

Functionalization of polymeric organolithium compounds. Oxidation

The oxidation of poly(styryl)lithium with molecular oxygen was investigated in the solid state (with and without N,N,N′, N′-tetramethylethylenediamine) in benzene (with and without N,N,N′, N′-tetramethylethylenediamine) and in benzene/tetrahydrofuran (THF) solutions. The oxidation products included the corresponding polystyrene dimer [(PS)₂], the dimeric poly(styrene) peroxide (PSO₂PS), poly(styrene) hydroperoxide (PSO₂H), and the hydroxyl-terminated polymer (PSOH). The hithertofore unreported macroperoxide (PSO₂PS) accounts for approximately 50% of the dimeric product obtained from poly(styryl)lithium oxidations in the presence of Lewis bases. The total amount of peroxide products was determined by iodometric titration in the presence of a phase-transfer catalyst, dicyclohexyl-18-crown-6. On the basis of the effect of polar additives on the amount of dimeric products, it is concluded that dimer formation in the air termination of polymeric organolithium compounds results from oxidation and not carbonation reactions.     

Conformational Analysis and Chromic Acid Oxidation. Oxidation Rates and Equilibrium Constants of Epimeric Alcohols

The linear free energy relationship of Sicher for relative reactivity towards chromic acid oxidation (ΔΔG) as a function of thermodynamic stability (ΔG) has been reexamined with 23 pairs of epimeric alcohols. The plot of ΔG vs. ΔG has a slope of 0.8, a correlation coefficient of 0.97 and a standard deviation of 0.23 kcal/mol on ΔΔG_Ox. The limitations of the relationship and the exceptions are discussed.     

Oxidation of Polyisoprene Popcorn Polymer. II. Gravimetric Analysis

Water, carbon dioxide, and condensable condensate produced during the oxidation of polyisoprene popcorn polymer were determined gravimetrically. For pure polyisoprene popcorn polymer from which 4.6% soluble polymer and volatiles were removed, the rates of water and carbon dioxide production during the early stages of the autoxidation were linear and amounted to approximately 2 moles of water and 0.2 moles of carbon dioxide for every 10 moles of oxygen reacted.

The generally accepted scheme for polyisoprene oxidation must be modified to account for the water production. Two possible routes for its synthesis are:

ROOH + ROOH → RO· + ROO· + H₂O

ROOH → RO· + ·OH

HO· + R → R· + H₂O     

二氧化硫的电化学氧化过程：Ⅱ.SO2在贵金属电极上的氧化机理

采用计时电位法、计时电流法和稳态极化曲线法研究了ＳＯ＿２在Ａｕ和Ｒｕ两种不同类型贵金属催化剂上的氧化过程，提出了ＳＯ＿２在这两类电极上的氧化机理。     

ChemInform Abstract: Oxidation State 10 Exists.

DFT electronic structure calculations indicate the existence of oxidation state 10 in the T_d structure of PtO₄²⁺.