Singlet oxygen-based photocatalytic oxygenation reactions have emerged as an efficient technology to synthesize value-added organic molecules. Among organic substrates, bio-sourced molecules such as amino acids or terpenes have a promising forecast as synthetic building blocks. A pseudo first-or...
In this article, we present a new, easy-to-implement assay for methionine γ-lyase (MGL)-catalyzed γ-elimination reactions of l-methionine and its analogues that produce α-ketobutyrate (α-KB) as product. The assay employs ultraviolet–visible (UV–Vis) spectrophotometry to continuously monito...
About 12% of the radioactivity of [Me-14C]methionine sulfoxide injected into rats was excreted in the urine in 24 h. N-Aceytlmethionine sulfoxide contained about 65% of the radioactivity excreted. The N-acetylcholamine sulfoxide was identified by its co-chromatography on paper with the chemicall...
In order to investigate the effects of hydroxyl radicals on the myosin of pork, with focus on reducible and non-reducible oxidation of specific cysteine and methionine residues, extracted myofibrillar protein from longissimus dorsi of pork was incubated with H2O2 for 24, 48 and 72 h, respectivel...
The electro-oxidation mechanism of free methionine and bound within different peptide sequences was investigated by voltammetry, at glassy carbon electrode, and mass spectrometry. It is proposed that the electro-oxidation of free methionine occurs in two steps, each involving the transfer of one...
This study aimed to explore the possibility of using methionine sulfone (Msn)-containing orbitides as indicators to evaluate the oxidation process of flaxseed oils. Results showed that after 4 days’ heating, oxidation values slightly increased (p > .05) with significant decrease in methionine (...
Electron paramagnetic resonance (EPR) study of gamma irradiated dl-2-amino-4-(Methylsulfonyl) butyric acid (dl-methionine sulfone, hereafter dl-ABA) single crystals and powder was performed at room temperature. It has been found that this compound indicates the existence of C.O2− and N.H2 radica...
α,α,ω,ω-Tetraphenyl-α,ω-alkadienes reacted with oligomethylene di(3-oxobutanoate)s in the presence of manganese(III) acetate at 100 °C under an argon atmosphere to give new 12 to 22-membered macrocyclic compounds which were two fused dihydrofuran rings in a one-step procedure.
The reaction of 3,3-diphenyl-2-propenyloxytetramethylene 3-oxobutanoate (14) with manganese(III) acetate dihydrate in boiling acetic acid caused the oxidative intramolecular radical cyclization to produce 13-methyl-11,11-diphenyl-3,8,12-trioxabicyclo[8.3.0]tridec-13-en-2-one (24) in 94% yield. A...
Alkyl 3-oxobutanoates (alkyl: methyl, ethyl, allyl, isobutyl, t-butyl) were reduced enantioselectively to the corresponding (S)-alcohols by the fungus Rhizopus arrhizus and other Rhizopus sp. The best result obtained was with t-butyl 3-oxobutanoate, which was reduced by R. arrhizus with 99% enan...
Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) is a branched-chain fatty acid which cannot be beta-oxidized due to the presence of the first methyl group at the 3-position. Instead, phytanic acid undergoes alpha-oxidation to produce pristanic acid (2,6,10,14-tetramethylpentadecanoic acid...
The electrospray mass spectra of the lanthanide (Ln)2,2,6,6-tetramethyl-3,5-heptanedione (thd) complexes Eu(thd)3, Gd(thd)3 and Yb(thd)3 were obtained from a methanol/water solution containing acetic acid. Protonated molecular ions Ln(thd)3H+ were obtained in each case. Extensive ligand exchange...
The standard molar enthalpies of formation of crystalline chelates M(thd)3, (M=Sc, Y, La; and thd=2,2,6,6-tetramethyl-3,5-heptanedionate), determined by reaction-solution calorimetry atT=(298.15±0.02) K, were found to be −(2317.83±11.7) kJ · mol−1, −(2386.1±11.4) kJ · mol−1, and −(2442.2±1...
Bismuth oxide films were deposited at 225–425 °C by direct liquid injection (DLI)-metal organic chemical vapor deposition (MOCVD) process with Bi(tmhd)3 (tmhd : 2,2,6,6-tetramethyl-3,5-heptanedione) dissolved in n-butylacetate. The deposition rate of Bi2O3 film was determined by surface reacti...
Room temperature adsorption and reaction of 2,2,6,6-tetramethyl-3,5-heptanedione (dpmH) on the Si(1 0 0)-2 × 1 surface has been studied with ultra-high vacuum scanning tunneling microscopy (UHV-STM) and temperature programmed desorption (TPD). The molecule is found to chemisorb as a mixture of ...
Solution-reaction calorimetry was used to determine the standard molar (p′=0.10 Mpa) enthalpies of formation of crystalline chelates Ln(thd)3 (Ln=Nd, Sm, Gd, Tb, Er, Tm, Yb, Lu and thd=2,2,6,6-tetramethyl-3,5-heptanedionate), at (T=298.15±0.02) K, to give: 40.54±1.21; 37.77±1.78; 8.06±0.80;...
The molecular level chemistry of 2,2,6,6-tetramethyl-3,5-heptanedione (dpmH) has been investigated on a Si(1 0 0)-2 × 1 surface. The dpmH compound is a β-diketone, whose deprotonated form is used as a ligand in chemical precursors for metal-organic chemical vapor deposition (MOCVD). A combinat...
Molecular structure, intramolecular hydrogen bonding (IHB) and vibrational frequencies of 2,2,6,6-tetramethyl-3,5-heptanedione (TMHD, also known as dipivaloylmethane), have been investigated by means of the density functional theory (DFT) calculations and IR and Raman spectroscopies. In addition...
Complexes of composition Th(NO3)4·3L (L = MeCONHEt [ea]), M(NO3)4·2.5L (M=Th, L = Mecon(Pri)2 (dipa) and M = U, L = ea and dipa), Pu(NO3)4·2L (L = ea and dipa) and UO2NO3·2L (L = dipa) have been prepared. Their IR, Raman (thorium compounds only) and electronic spectra are reported.
By analysis of infrared and NMR spectra, N-ethylacetamide, in the liquid state, in polar and nonpolar media, in a broad temperature and concentration range, was found to exist in the form of a single pair of equivalent mirror image conformers, with the conformational angle φ in the vicinity of ...
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