- The toxic aldehyde, 4-hydroxy-2-trans-nonenal (HNE) formation in natural and imitation mozzarella cheeses: Heat treatment effects
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The formation of 4-hydroxy-2-trans-nonenal (HNE), a toxic aldehyde formation, was investigated in heat treated imitation Mozzarella cheeses which are made with vegetable oils and in natural Mozzarella cheeses which contain dairy fats. The cheeses were hea
- Han, In Hwa,Csallany, A. Saari
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- Formation of potentially toxic carbonyls during oxidation of triolein in the presence of alimentary antioxidants
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Abstract: A relation between oil uptake and cancer as well as induction of hepatic inflammation was shown earlier. It is discussed that the main oil oxidation products—hydroperoxides and carbonyls—might be the reason for the mentioned diseases. In this manuscript quantitative determination of aldehydes which are formed during oxidation of triolein—as a model substance—using the Rancimat 679 is described. The oxidation of 11?g of triolein is carried out at 120?°C sparging air with a flow of 20?dm3/h for 10?h. A series of aliphatic aldehydes starting from hexanal to decanal as well as decenal was identified by LC–MS/MS and quantified as DNPH derivatives. In addition, the total amount of carbonyls was determined. Based on the calibration with hexanal, all other dominant substances were in the similar concentration range with maximum concentrations of 1.6?μmol/cm3 of hexanal, 2.3?μmol/cm3 of heptanal, 2.5?μmol/cm3 of octanal, 3.2?μmol/cm3 of nonanal, 4.0?μmol/cm3 of decanal after 6?h. The total amount of carbonyls reached a maximum after 6?h being 27?μmol/cm3 for triolein without antioxidant. The results of this investigation will be a basis for further toxicological studies on oxidized oils.
- Damanik, Marini,Murkovic, Michael
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p. 2031 - 2035
(2017/10/26)
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- Selective reduction of carboxylic acids to aldehydes catalyzed by B(C 6F5)3
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B(C6F5)3 efficiently catalyzes hydrosilylation of aliphatic and aromatic carboxylic acids to produce disilyl acetals under mild conditions. Catalyst loadings can be as low as 0.05 mol %, and bulky tertiary silanes are favored to give selectively the acetals. Acidic workup of the disilyl acetals results in the formation of aldehydes in good to excellent yields.
- Bezier, David,Park, Sehoon,Brookhart, Maurice
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p. 496 - 499
(2013/03/29)
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- Analysis of carbonyl compounds in sea buckthorn for the evaluation of triglyceride oxidation, by enzymatic hydrolysis and derivatisation methodology
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Carbonyl compounds formed in sea buckthorn berry (Hippophae rhamnoides) and oil samples as a result of lipid oxidation were determined by enzymatic hydrolysis followed by derivatisation with 2,4-dinitrophenylhydrazine and analysed by LC-UV and electrospra
- Mathew, Sindhu,Grey, Carl,Rumpunen, Kimmo,Adlercreutz, Patrick
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experimental part
p. 1399 - 1405
(2012/02/03)
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- Synthesis and properties of 4,9-methanoundecafulvenes and their transformation to 3-substituted 7,12-methanocycloundeca[4,5]furo[2,3-d] pyrimidine-2,4(1H,3H)-diones: Photo-induced autorecycling oxidizing reaction toward amines
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The synthesis and properties of 4,9-methanoundecafulvene [5-(4,9-methanocycloundeca-2′,4′,6′,8′, 10′-pentaenylidene)pyrimidine-2,4,6(1,3,5H)-trione] derivatives 8a,b were studied. Their structural characteristics were investigated on the basis of the 1H and 13C NMR and UV-vis spectra. The rotational barrier (ΔG?) around the exocyclic double bond of 8a was found to be 12.55 kcal mol-1 by the variable temperature 1H NMR measurement. The electrochemical properties of 8a,b were also studied by CV measurement. Furthermore, the transformation of 8a,b to 3-substituted 7,12-methanocycloundeca[4,5]furo[2,3-d]pyrimidine-2,4(1H,3H)-diones 16a,b was accomplished by oxidative cyclization using DDQ and subsequent ring-opening and ring-closure. The structural details and chemical properties of 16a,b were clarified. Reaction of 16a with deuteride afforded C13-adduct 19 as the single product, and thus, the methano-bridge controls the nucleophilic attack to prefer endo-selectivity. The photo-induced oxidation reaction of 16a and a vinylogous compound, 3-methylcyclohepta[4,5]furo[2,3-d]pyrimidine-2,4(3H)-dione 2a, toward some amines under aerobic conditions were carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) with the recycling number of 6.1-64.0 (for 16a) and 2.7-17.2 (for 2a), respectively.
- Naya, Shin-Ichi,Yamaguchi, Yohei,Nitta, Makoto
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p. 7384 - 7391
(2007/10/03)
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- Novel synthesis, properties, and NAD+-NADH type redox ability of 1,3-dimethylcyclohepta[4,5]pyrrolo[2,3-d]pyrimidine-2,4(1,3H)-dionylium ions annulated with additional pyrrolo[2,3-d]pyrimidine-1,3(2,4H)-dione and furan analogue, and their hydride adducts
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A convenient preparation of novel cations 11a,b+·BF 4- and 12a,b+·BF4 -, which are derived from annulation of the 1,3-dimethylcyclohepta[4, 5]pyrrolo[2,3-d]pyrimidine-2,4(1,3H)-dionylium ion with additional pyrrolo[2,3-d]pyrimidine-1,3(2,4ii)-dione and a furan analogue, was accomplished by a novel oxidative cyclization of 1,7-dihydro-7-[1′,3′-dimethyl- 2′,4′(1′,3′H)-dioxo-6′-(phenylamino) -pyrimidin-5′-yl]-1,3-dimethyl-10-phenylcyclohepta[4,5]pyrrolo[2,3-d] pyrimidine-2,4(1,3H)-dione 9 and its furan-analogue by using DDQ or photoirradiation under aerobic conditions. Structural characteristics of 11a,b+ and 12a,b+ were clarified on inspection of the UV-vis and NMR spectral data as well as X-ray crystal analyses. The stability of cations 11a,b+ and 12a,b+ is expressed by the pK R+ values that were determined spectrophotometrically to be 10.7-12.6. The electrochemical reduction of 11a,b+·BF 4 and 12a,b+·BF4- exhibited reduction potential at -0.93 to -1.00 (V vs Ag/AgNO3). The first reduction potential of 11a+ was reversible due to steric hindrance of two phenyl groups. The photoinduced oxidation reaction of 11a,b +·BF4- and 12a,b+· BF4- toward some amines under aerobic conditions was carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) with the recycling numbers of 0.6-30.3. Furthermore, as an example of the NAD+-NADH models, the reduction of a pyruvate analogue and some carbonyl compounds with the hydride-adduct of 11a+-BF4- was accomplished for the first time to give the corresponding alcohol derivatives.
- Naya, Shin-Ichi,Nishimura, Junya,Nitta, Makoto
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p. 9780 - 9788
(2007/10/03)
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- Ring transformation of cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)- dionylium ion to the corresponding pyrrole derivatives via troponeimine intermediates: Photo-induced autorecycling oxidizing reactions of some amines
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Ring transformation of 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]furan- 8(7H),10(9H)-dionylium tetrafluoroborate 4+·BF 4- to 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]pyrrrole- 8(7H),10(9H)-dionylium tetrafluoroborate 6a-d+·BF 4- consists of the reaction of 4+· BF4- with amines and subsequent exchange of the counter-ion using aq. HBF4. Reactions of 4+·BF 4- with aniline and 4-substituted anilines afforded the corresponding pyrrole derivatives 6a-c+·BF4 - directly in good yields. On the other hand, reaction of 4 +·BF4- with benzylamine gave the troponeimine intermediate 9, which was not converted to 6d+· BF4- and reverted to 4+·BF 4- by adding HBF4; however, it was converted to 6d+·BF4- upon treatment with (COCl)2 or SOCl2, followed by exchange of the counter-ion. In a search for the characteristics of 9, inspection and comparison of the X-ray crystal analyses, NMR and UV-vis spectra, and CV measurement of 9 and N,N-disubstituted troponeimine derivatives 12 were carried out to suggest the remarkable structure of 12 having ionic C-O bonding between the imine-carbon atom and the oxygen atom of the barbituric acid moiety in the solid state. Thus, characteristics of 9 were ascribed to the sterically hindered and favorable conformation of N-protonated troponeimine intermediates. Furthermore, novel photo-induced oxidation reactions of a series of 4+·BF 4-, 5+·BF4-, and 6a,e+·BF4- towards some amines under aerobic conditions were carried out to give the corresponding imines in 455-8362% yields [based on compounds 4+, 5+, and 6a,e +], suggesting the oxidation reaction occurs in an autorecycling process. Mechanistic aspects of the amine-oxidation reaction are also postulated.
- Naya, Shin-Ichi,Nitta, Makoto
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p. 9139 - 9148
(2007/10/03)
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- New synthesis, properties, and oxidizing ability of 1,3-dimethyl-5,10- methanocycloundeca[4,5]furo[2,3-d]pyrimidin-2,4(1,3H)-dionylium tetrafluoroborate
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A novel synthesis of 1,3-dimethyl-5,10-methanocycloundeca[4,5]furo[2,3-d] pyrimidin-2,4(1,3H)-dionylium tetrafluoroborate (10+·BF 4-) was accomplished by the reaction of 3,8-methano[11]-annulenone with dimethylbarbituric acid and following acidic cyclization, albeit in low yield. Remarkable structural characteristics were suggested on inspection of the spectral data and MO calculation, and it was clarified that the positive charge is largely localized at the C11. The pK R+ value of cation 10+ was determined spectrophotometrically to be 4.6, which is much smaller by 4.1 pH unit than that of 1,3-dimethyl-7,12-methanocycloundeca[4,5]furo[2,3-d]pyrimidin-2,4(1,3H)- dionylium tetrafluoroborate (pKR+ = 8.7). This value is also smaller by 1.6 pH unit than that of the parent 1,6-methano[11]annulenylium ion (pK R+ = 6.2). The feature is rationalized on the basis of the perturbation derived from the bond fixation of the parent cation. The electrochemical reduction of 10+ exhibited less negative reduction potential at -0.39 (V vs Ag/AgNO3) upon cyclic voltammetry (CV). In a search for reactivity, reactions of 10+ with some nucleophiles, hydride and diethylamine, were carried out to give mixtures of C11- and C13-adducts. In both reactions, the methano-bridge controls the nucleophilic attacks to the C13 to favor exo selectivity. The photoinduced autorecycling oxidation reactions of 10+·BF4- toward some amines under aerobic conditions were carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) in 719-3286% yield (recycling number of 10+·BF 4-: 7.2-32.9).
- Naya, Shin-Ichi,Warita, Masato,Mitsumoto, Yuhki,Nitta, Makoto
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p. 9184 - 9190
(2007/10/03)
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- Oxidation of unactivated primary aliphatic amines catalyzed by an electrogenerated 3,4-azaquinone species: A small-molecule mimic of amine oxidases
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High catalytic performance of the electrogenerated amine oxidase mimic 3,4-iminoquinone 1ox is observed under metal-free conditions in the chemoselective oxidation reaction of unactivated primary aliphatic amines.
- Largeron, Martine,Neudorffer, Anne,Fleury, Maurice-Bernard
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p. 1026 - 1029
(2007/10/03)
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- The 2-methylbut-2-enyl(diphenyl)silyl group: A silyl group easily converted to hydroxyl in the presence of a 1,2-disubstituted C=C double bond
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The 2-methylbut-2-enyl(diphenyl)silyl group can be introduced into a variety of organic structures by way of the cuprate reagent 4, and it can then be converted into a hydroxyl group, even in the presence of a C=C double bond, unlike the dimethyl(phenyl)silyl group.
- Fleming, Ian,Winter, Stephen B. D.
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p. 7287 - 7290
(2007/10/02)
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