Oxidative Ring-Cleavage of Catechol in meta-Position by Superoxide

1989 ◽  
Vol 44 (3-4) ◽  
pp. 207-211 ◽  
Author(s):  
Rudolf Müller ◽  
Franz Lingens
Keyword(s):  
Spectroscopic Data ◽  
Mass Spectra ◽  
Room Temperature ◽  
Picolinic Acid ◽  
Uv Spectra ◽  
Cleavage Product ◽  
Ring Cleavage ◽  
Meta Position ◽  
Acid Semialdehyde ◽  
Yellow Compound

Abstract Superoxide reacts with catechol in dimethylsulfoxide to form a yellow product. The structure of this product was established by different methods. UV-spectra of the yellow compound corresponded under all circumstances to those of enzymatically produced 2-hydroxymuconic acid semialdehyde. In the presence of ammonia the product was converted to picolinic acid. The UV - spectra, the retention times in GC and HPLC and the mass spectra after methylation corresponded to those of authentic picolinic acid. Thus, the yellow reaction product was unequivocally identified as 2-hydroxymuconic acid semialdehyde. The formation of the me/a-cleavage product was only observed at low catechol concentrations (<2 mM) , at higher concentrations the product was not formed. The reaction was complete within 10 min at room temperature. Spectroscopic data suggest a first intermediate in the reaction with λmax = 804 nm, 772 nm and 660 nm.

Differential Roles of Three Different Upper Pathway Meta Ring Cleavage Product Hydrolases in the Degradation of Dibenzo- p -dioxin and Dibenzofuran by Sphingomonas wittichii RW1

2021 ◽  
Author(s):  
Thamer Y. Mutter ◽  
Gerben J. Zylstra
Keyword(s):  
Gene Knockout ◽  
Sole Source ◽  
Cleavage Product ◽  
Ring Cleavage ◽  
Catabolic Pathway ◽  
Double Knockout ◽  
Cleavage Enzyme ◽  
Sphingomonas Wittichii ◽  
Physiological Approach

Sphingomonas wittichii RW1 grows on the two related compounds dibenzofuran (DBF) and dibenzo- p -dioxin (DXN) as the sole source of carbon. Previous work by others (P.V. Bunz, R. Falchetto, and A.M. Cook. Biodegradation 4:171-8, 1993, doi: 10.1007/BF00695119) identified two upper pathway meta cleavage product hydrolases (DxnB1 and DxnB2) active on the DBF upper pathway metabolite 2-hydroxy-6-oxo-6-(2-hydroxyphenyl)-hexa-2,4-dienoate. We took a physiological approach to determine the role of these two enzymes in the degradation of DBF and DXN by RW1. Single knockouts of either plasmid located dbfB1 or chromosome located dbfB2 had no effect on RW1 growth on either DBF or DXN. However, a double knockout lost the ability to grow on DBF but still grew normally on DXN demonstrating that DbfB1 and DbfB2 are the only hydrolases involved in the DBF upper pathway. Using a transcriptomic-guided approach we identified a constitutively expressed third hydrolase encoded by the chromosomally located SWIT0910 gene. Knockout of SWIT0910 resulted in a strain that no longer grows on DXN but still grows normally on DBF. Thus the DbfB1 and DbfB2 hydrolases function in the DBF but not the DXN catabolic pathway and the SWIT0190 hydrolase functions in the DXN but not the DBF catabolic pathway. Importance S. wittichii RW1 is one of only a few strains known to grow on DXN as the sole course of carbon. Much of the work deciphering the related RW1 DXN and DBF catabolic pathways has involved genome gazing, transcriptomics, proteomics, heterologous expression, and enzyme purification and characterization. Very little research has utilized physiological techniques to precisely dissect the genes and enzymes involved in DBF and DXN degradation. Previous work by others identified and extensively characterized two RW1 upper pathway hydrolases. Our present work demonstrates that these two enzymes are involved in DBF but not DXN degradation. In addition, our work identified a third constitutively expressed hydrolase that is involved in DXN but not DBF degradation. Combined with our previous work, this means that the RW1 DXN upper pathway involves genes from three very different locations in the genome: an initial plasmid-encoded dioxygenase and a ring cleavage enzyme and hydrolase encoded on opposite sides of the chromosome.

Structural and Electronic Properties of the Iron(II) and Nickel(II) Bis(ligand) Complexes of 6-(5-Methyl-1,2,4-oxadiazol-3-yl)-2,2′-bipyridine— a Terpyridine-Based Tridentate

1999 ◽  
Vol 52 (7) ◽  
pp. 673 ◽  
Author(s):  
Bradley J. Childs ◽  
Marcia L. Scudder ◽  
Donald C. Craig ◽  
Harold A. Goodwin
Keyword(s):  
Electronic Properties ◽  
Spectroscopic Data ◽  
Room Temperature ◽  
Spin Transition ◽  
Iron Complex ◽  
Ligand Field ◽  
Monoclinic Space Group ◽  
Space Group ◽  
C 23 ◽  
Structural And Electronic Properties

Iron(II) and nickel(II) bis(ligand) complexes of 6-(5-methyl-1,2,4-oxadiazol-3-yl)-2,2′-bipyridine (L) are described. The ligand field in the iron complex is close to that at the singlet ( 1 A1) ? quintet ( 5 T2) crossover and magnetic and Mössbauer spectral evidence indicates that a spin transition occurs in salts of the iron complex but is centred above room temperature. The structures of [FeL2] [CF3SO3]2.CH3CN and [NiL2] [BF4]2.CH3CN were determined and both are very similar to the structures of the corresponding terpyridine complexes. Spectroscopic data indicate that for the iron complex π-interaction between the metal and the ligand is less than that in the terpyridine system. [FeL2] [CF3SO3]2.CH3CN is monoclinic, space group P 21/c; a 8 . 232(5), b 25 . 273(10), c 17 . 306(10) Å, β 92 . 37(3)°, Z 4; [NiL2] [BF4]2.CH3CN is monoclinic, space group P 21/c; a 8 . 136(2), b 17 . 558(2), c 23 . 783(7) Å, β 109 . 32(1)°, Z 4.

Chlor(trifluorphosphan)gold(I), eine einfache flüchtige Notizen: Goldverbindung/Chloro(trifluorophosphane)gold(I), a Simple Volatile Gold Compound

1992 ◽  
Vol 47 (4) ◽  
pp. 591-593 ◽  
Author(s):  
Werner Fuß ◽  
Martin Rühe
Keyword(s):  
Vapor Pressure ◽  
Mass Spectra ◽  
Room Temperature ◽  
Gold Compound

(PF3)AuCl was prepared from PF3 and Au2Cl6 in SOCl2 as a solvent. It is more stable than the analogous CO complex. It has a vapor pressure of about 10-4 mbar at room temperature. Its IR , NMR and mass spectra are reported.

scholarly journals Spontaneous Magnetization and Optical Activity in the Chiral Series {(L-proline)nV[Cr(CN)6]x} (0 < n < 3)

2020 ◽  
Vol 6 (1) ◽  
pp. 12
Author(s):  
Bárbara Rodríguez-García ◽  
Jose Ramon Galan-Mascaros
Keyword(s):  
Spectroscopic Data ◽  
Room Temperature ◽  
Spontaneous Magnetization ◽  
Magnetic Hysteresis ◽  
Magnetic Ordering ◽  
Structural Features ◽  
Natural Amino Acid ◽  
Amorphous Nature ◽  
Redox Stability ◽  
Circular Dichroic

The incorporation of the natural amino acid L-proline in the synthesis to vanadium-chromium Prussian blue derivatives results in materials exhibiting magnetic ordering including chiral magnetic centers. Although the amorphous nature of these materials makes difficult to assess the structural features of these proline-containing compounds, magnetic and spectroscopic data confirms their multifunctionality. They exhibit high-temperature magnetic ordering (Tc < 255 K) and a circular dichroic signal, representing the molecule-based chiral magnets with the highest ordering temperatures reported to date. In addition, the presence of chiral L-proline (or D-proline) has additional benefits, including higher redox stability and the appearance of magnetic hysteresis. The latter was not observed in the parent compounds, the series of room temperature molecule-based magnets V[Cr(CN)6]x.

Polysulfonylamine, XV [1] Synthese von N,N,N′,N′-Tetramesyl-dicarbonsäurediamiden. Cyclisierung von N,N,N′,N′-Tetramesyl-bernsteinsäurediamid zu γ-DimesyIamino-Δβγ-butenolid / Polysulfonylamines, XV [1]. Synthesis of N,N,N′,N′-Tetramesyl Dicarboxylic Diamides. Cyclization of N,N,N′,N′-Tetramesyl Succinic Diamide to γ-Dimesylamino-Δβγ-butenolide

1989 ◽  
Vol 44 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Armand Blaschette ◽  
Karin Linoh ◽  
Dietrich Koch ◽  
Ludger Ernst
Keyword(s):  
Succinic Acid ◽  
Acid Derivative ◽  
Analytical Methods ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Sodium Succinate ◽  
Ring Closure ◽  
Ring Cleavage ◽  
New Compounds ◽  
C Nmr

N, N, N′, N′ -Tetramesyl dicarboxylic diamides Ms2NC(O)-Q-C(O)NMs2 [Q = (CH2)n with n = 0 (2a), 2 (2b), 3 (2c), 4 (2d); Q = o-phenylene (2e)] were prepared by reacting AgNMs2 (1) with the appropriate dicarboxylic dichlorides in acetonitrile at room temperature (2a, 2 c-2e) or at 0 °C (2b), respectively. Under similar conditions, malonic dichloride undergoes an elimination, forming AgCl, HNMs2 and probably polymeric C3O2. At 20 °C in CH3CN, the succinic acid derivative 2b eliminates one mole of HNMs2 and, by ring closure, yields γ-dimesylamino-Δβγ- butenolide (4a), the first example of a stable γ-amino-Δβγ-butenolide. Treatment of 4a with aqueous NaOH results in the formation of NaNMs2 and sodium succinate. Crystalline 4a is thermally stable at 100 °C; no signs of an isomerization 4a → γ-dimesylamino-Δαγ-butenolide could be detected. Unlike the structurally related α-angelicalactone (4c), whose bromination affords the saturated dibromolactone 9 as a mixture of cis- and mws-isom ers, 4a adds bromine (20 °C, CHCl3) under ring cleavage to form BrC(O)CH2CHBrC(O)NMs2 (7). The new compounds 2, 4a and 7 as well as the stereoisomers of 9 were characterized by spectroscopic (1H and 13C NMR, MS, IR) and analytical methods. In order to obtain reference values for the chemical shifts of 7, the following new compounds were prepared: CH3(CH2)2C(O)NMs2 (10c, from 1 and butvryl chloride); CH3CH2CHBrC(O)NMs2 (12c, from 1 and 2-bromobutyryl bromide); C2H5OC(O)CH 2CHBrC(O)NMs2 (13, from 7 with ethanol and from 4a by simultaneous reaction with bromine and ethanol).

scholarly journals Prenylated Flavones from Artocarpus Lanceifolius and their Cytotoxic Properties against P-388 Cells

2009 ◽  
Vol 4 (7) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Iqbal Musthapa ◽  
Jalifah Latip ◽  
Hiromitsu Takayama ◽  
Lia D. Juliawaty ◽  
Euis H. Hakim ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Mass Spectra ◽  
Cytotoxic Effect ◽  
Methanol Extract ◽  
2D Nmr ◽  
Tree Bark ◽  
Prenylated Flavones ◽  
Murine Leukemia

New prenylated flavones, artoindonesianins Z-4 and Z-5, together with four known prenylated flavones, artonin E, 12-hydroxyartonin E, artobiloxanthone, and cycloartobiloxanthone, have been isolated from the methanol extract of the tree bark of Artocarpus lanceifolius. The structures of these compounds were determined on the basis of spectroscopic data, including UV, IR, 1D and 2D NMR, and mass spectra. The cytotoxic effect of the isolated compounds against murine leukemia P-388 cells is described.

scholarly journals Regioselective Three Component Domino Synthesis of Polyhydrospiro[indoline-3,3'-pyrrolizine]-2-one via [3+2] Cycloaddition Reaction

2019 ◽  
Vol 31 (3) ◽  
pp. 613-616
Author(s):  
Vishwa Deepak Tripathi ◽  
Akhilesh Kumar Shukla ◽  
Hasan Shamran Mohammed
Keyword(s):  
Ir Spectra ◽  
Multicomponent Reaction ◽  
Elemental Analysis ◽  
13C Nmr ◽  
Mass Spectra ◽  
Room Temperature ◽  
Cycloaddition Reaction ◽  
Synthetic Chemistry ◽  
1H And 13C Nmr ◽  
Orbital Interactions

In present work, we have reported the synthesis and characterisation of novel hexahydrospiro[indoline-3,3′-pyrrolizine]-2-one derivatives in good to excellent yields via [3+2] cycloaddtion reaction in regioselective manner. These compounds were synthesized via multicomponent reaction of substituted 3-cinnamoyl-4-hydroxy-6-methyl-2H-pyran-2-one, isatin, L-proline at room temperature. All the synthesized hexahydrospiro molecules were characterized by 1H and 13C NMR, IR spectra, mass spectra and elemental analysis. Regioselectivity in synthesized molecules were also explained on the basis of secondary orbital interactions. A simple and facile methodology is developed which has great importance in synthetic chemistry.

Nitrogen Isotope Exchange between Liquid N2O3 and NO at Low Temperature and Elevated Pressure

1963 ◽  
Vol 18 (2) ◽  
pp. 235-241 ◽  
Author(s):  
E. U. Monse ◽  
Lois Nash Kauder ◽  
W. Spindel
Keyword(s):  
Low Temperature ◽  
Separation Factor ◽  
Isotope Exchange ◽  
Spectroscopic Data ◽  
Room Temperature ◽  
Nitrogen Isotopes ◽  
Nitrogen Isotope ◽  
Elevated Pressure ◽  
Single Stage ◽  
Stage Separation

The single stage separation factor, a, for nitrogen isotope exchange between liquid N2O3—N2O4-mixtures and their vapor has been measured at temperatures ranging from — 76°C to room temperature and pressures between 1 atm. and 7.4 atm.At —76°C and 1 atm., α = 1.061 ± 0.003;at —23°C and 1 atm., α=1.034 ± 0.002;at +23°C and 2.1 atm., α=1.017 ± 0.002;at +23°C and 7.4 atm., α=1.030 ± 0.002.The results are compared with values, calculated from spectroscopic data for N2O3, N2O4, NO and NO2. The value of α = 1.030 found at room temperature and 7.4 atm. pressure enhances the usefulness of the N2O3—NO-system for separating the nitrogen isotopes, since it eliminates the need of refrigeration.

Photolysis of 2,5- and 2,4-Dimethylpyrrole Vapors at Room Temperature

1972 ◽  
Vol 50 (11) ◽  
pp. 1678-1689 ◽  
Author(s):  
E. Chung Wu ◽  
Julian Heicklen
Keyword(s):  
Excited State ◽  
Free Radical ◽  
Room Temperature ◽  
Low Pressure ◽  
Incident Radiation ◽  
Ring Cleavage ◽  
Incident Wavelength ◽  
First Order ◽  
Electronically Excited State ◽  
Electronically Excited

Both 2,5- and 2,4-dimethylpyrrole vapors at pressures from 0.05 to 0.70 Torr were irradiated at 2139 and 2288 Å at room temperature. The products were H2, CH4, C2H6, and polymer. No ring cleavage products were found. Φ{H2} and Φ{CH4} were remarkably insensitive to which pyrrole was used, its pressure,Ia, or the wavelength of the incident radiation. They were ~0.10–0.15 and ~0.01–0.02, respectively. Φ{C2H6} was comparable to Φ{CH4} and was also invariant to which substrate was used or the incident wavelength. However Φ{C2H6} did increase at low pressure or as Ia was reduced.The effect of scavengers showed that the products were produced mainly from free radical precursors. The main primary steps are:[Formula: see text]where DMP* is an electronically excited state of the dimethylpyrrole and Fa and Fb are radical fragments. Experiments with quenching gases showed that DMP* could be quenched, but that this reaction was less important than the first-order steps below 1 Torr.

Nano ZrO2: an efficient, recyclable, and inexpensive catalyst for diastereoselective three-component Mannich reactions

2014 ◽  
Vol 92 (7) ◽  
pp. 659-664 ◽  
Author(s):  
M. Saeed Abaee ◽  
Elahe Akbarzadeh ◽  
Abbas Shockravi ◽  
Mohammad M. Mojtahedi ◽  
Hamid Reza Khavasi
Keyword(s):  
Spectroscopic Data ◽  
Room Temperature ◽  
Aromatic Aldehydes ◽  
Significant Loss ◽  
Mannich Reactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Aniline Derivatives ◽  
High Yields ◽  
Acyclic Ketones

A facile procedure is developed for the three-component Mannich reactions of several heterocyclic, homocyclic, and acyclic ketones by using catalytic quantities of nano ZrO2. As a result, the starting ketones undergo rapid reactions with a variety of aromatic aldehydes and aniline derivatives at room temperature to produce stereoselectively high yields of the corresponding anti β-amino ketones. Interestingly, the catalyst could be recycled for several runs in a row without significant loss of its activity. The structure of the products was assigned based on their spectroscopic data and the anti stereoselectivity was confirmed by X-ray crystallography.

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