Chromous chloride reduction VII. Stereochemistry and structure of the major product employed in the confirmation of endrin residues

1972 ◽  
Vol 8 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Alfred S. Y. Chau ◽  
R. J. Wilkinson
Keyword(s):  
Major Product ◽  
Chromous Chloride

Confirmation of Pesticide Residues Identity. X. Mirex

1978 ◽  
Vol 61 (6) ◽  
pp. 1475-1480
Author(s):  
Alfred S Y Chau ◽  
John M Carron ◽  
Hung Tse
Keyword(s):  
Retention Time ◽  
Reductive Dechlorination ◽  
Pesticide Residues ◽  
Room Temperature ◽  
Major Product ◽  
Chromatographic Retention ◽  
Liquid Chromatographic ◽  
Chromous Chloride

Abstract Three procedures using 3 different ratios of chromous chloride and acetone at room temperature or 55–60°C are described for confirming the presence of Mirex (dodecachlorooctahydro- l,3,4-metheno-2H-cyclobuta [cd] pentalene). Each procedure gives a different major product with a different gas-liquid chromatographic retention time. The factors that could affect this reductive dechlorination were also studied. The procedures can detect, respectively, 1.1, 0.7, and 0.5 times the amount of the Mirex standard (taken as 1.0) used in the investigation.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

Flavor Profile Analysis and GC/MS Detection of Phenolic Iodinated Disenfection Byproducts in Drinking Water for the USA Space Program

1999 ◽  
Vol 40 (6) ◽  
pp. 45-51 ◽  
Author(s):  
Andrea M. Dietrich ◽  
Susan Mirlohi ◽  
Willian F. DaCosta ◽  
Jennifer Peters Dodd ◽  
Richard Sauer ◽  
...  
Keyword(s):  
Drinking Water ◽  
Potable Water ◽  
Profile Analysis ◽  
Major Product ◽  
Space Program ◽  
Odor Threshold ◽  
Odor Evaluation ◽  
The Usa ◽  
Flavor Profile Analysis ◽  
Flavor Profile

Reactions of iodine and phenol were investigated to determine which iodophenols were produced and their odor properties. The research was performed in support of the USA space program that applies iodine to disinfect potable water for spacecraft use. Higher concentrations (50 mg/l) and higher iodine:phenol (e.g. 10:1) ratios resulted in the formation of greater iodophenol concentrations and higher substituted iodophenols. The reactions were fast and nearly complete within 1 hour. For pH 5.5 and 8 and all iodine:phenol ratios, formation of monosubstituted compounds indicated that 2-iodophenol was favored over 4-iodophenol. At the intermediate iodine:phenol ratios of 1:1 and 2:1, substantial amounts of the diiophenols formed and persisted for up to 32 days. The diiodophenols were not detected at iodine:phenol ratios of 0.2:1 and 10:1. The compound 2,4,6-triiodophenol was the major product formed at a 10:1 iodine:phenol ratio and the formation of this trisubstituted phenol appeared nearly complete. Odor evaluation indicated that the iodophenols have much lower odor threshold concentrations (OTC) than phenol. The 2- and 4- iodophenol had OTC values of ≅ 1 and 500 μg/l, respectively, with odors described as “medicinal, phenol, chemical”.

Evaluation of the Radioprotective Effects of Melatonin Against Ionizing Radiation-Induced Muscle Tissue Injury

2019 ◽  
Vol 12 (3) ◽  
pp. 247-255 ◽  
Author(s):  
Dheyauldeen Shabeeb ◽  
Mansoor Keshavarz ◽  
Alireza Shirazi ◽  
Gholamreza Hassanzadeh ◽  
Mohammed Reza Hadian ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Gastrocnemius Muscle ◽  
Tissue Injury ◽  
Histopathological Examination ◽  
Compound Action Potential ◽  
Optimal Dose ◽  
Treatment Method ◽  
Major Product ◽  
Muscle Tissues ◽  
Radiation Induced

Background: Radiotherapy (RT) is a treatment method for cancer using ionizing radiation (IR). The interaction between IR with tissues produces free radicals that cause biological damages.As the largest organ in the human body, the skeletal muscles may be affected by detrimental effects of ionizing radiation. To eliminate these side effects, we used melatonin, a major product secreted by the pineal gland in mammals, as a radioprotective agent. Materials and Methods: For this study, a total of sixty male Wistar rats were used. They were allotted to 4 groups: control (C), melatonin (M), radiation (R) and melatonin + radiation (MR). Rats’ right hind legs were irradiated with 30 Gy single dose of gamma radiation, while 100 mg/kg of melatonin was given to them 30 minutes before irradiation and 5 mg/ kg once daily afternoon for 30 days. Five rats in each group were sacrificed 4, 12 and 20 weeks after irradiation for histological and biochemical examinations. Results: Our results showed radiation-induced biochemical, histological and electrophysiological changes in normal rats’ gastrocnemius muscle tissues. Biochemical analysis showed that malondialdehyde (MDA) levels significantly elevated in R group (P<0.001) and reduced significantly in M and MR groups after 4, 12, and 20 weeks (P<0.001), However, the activity of catalase (CAT) and superoxide dismutase(SOD)decreased in the R group and increased in M and MR groups for the same periods of time compared with the C group (P<0.001), while melatonin administration inverted these effects( P<0.001).Histopathological examination showed significant differences between R group for different parameters compared with other groups (P<0.001). However, the administration of melatonin prevented these effects(P<0.001). Electromyography (EMG) examination showed that the compound action potential (CMAP) value in the R group was significantly reduced compared to the effects in the C and M groups after 12 and 20 weeks (P<0.001). The administration of melatonin also reversed these effects (P<0.001). Conclusion: Melatonin can improve biochemical, electrophysiological and morphological features of irradiated gastrocnemius muscle tissues.Our recommendation is that melatonin should be administered in optimal dose. For effective protection of muscle tissues, and increased therapeutic ratio of radiation therapy, this should be done within a long period of time.

Reactivity of γ-Chloro-gem-trichloroalkanes with Chromous Chloride.

ChemInform ◽  
2006 ◽  
Vol 37 (44) ◽  
Author(s):  
Steve Tisserand ◽  
Romain Bejot ◽  
Celia Billaud ◽  
De Run Li ◽  
J. R. Falck ◽  
...  
Keyword(s):  
Chromous Chloride

Proteolysis of caseins and the proteose-peptone fraction of bovine milk

1983 ◽  
Vol 50 (3) ◽  
pp. 275-290 ◽  
Author(s):  
Anthony T. Andrews ◽  
Efstathios Alichanidis
Keyword(s):  
Gel Electrophoresis ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Major Product ◽  
Natural Course ◽  
Pasteurized Milk ◽  
Proteose Peptone ◽  
History Of

SummaryThe proteolysis of highly purified samples of αs1-, αs2-, β-and κ-caseins by porcine plasmin and by bovine plasminogen with urokinase has been examined principally by gel electrophoresis. The resulting peptide band patterns were compared with those of total proteose-peptone (TPP) samples prepared from fresh and stored raw and pasteurized milk, and also with those obtained during the natural course of proteolysis by indigenous enzymes in milk during storage. TPP was found to contain at least 38 components detectable by a single electrophoresis run. Apart from residual traces of whey proteins and intact caseins nearly all of these components were fragments of caseins produced by indigenous plasmin, with products from the breakdown of αs1- and β-casein predominating. Over 90 % of TPP has been accounted for in this way. A fragment consisting of residues 29–105 of β-casein was isolated and characterized from both stored milk and from plasmin digests of β-casein. This fragment was a relatively major product of the natural proteolysis occurring during storage of milk, but contrary to a report in the literature it was not the same as proteose-peptone component 8-slow. Since many of the components of TPP resulted from proteolysis, the composition of TPP was found to vary according to the time and temperature of storage of the milk from which it was prepared. Thus, while the proteose-peptone fraction of milk can easily be defined operationally it cannot be rigorously defined in terms of its composition unless the history of the milk is also defined.

scholarly journals Zinc-mediated Reductive Dimerization Cyclization of Ethyl Arylmethylidenecyanoacetates in Aqueous Media

1999 ◽  
Vol 23 (7) ◽  
pp. 448-449
Author(s):  
Lei Wang ◽  
Yongmin Zhang
Keyword(s):  
Aqueous Media ◽  
Major Product ◽  
Trans Form ◽  
Reductive Dimerization

Zinc-mediated reductive dimerization–cyclization of ethyl arylmethylidenecyanoacetates occurs to give diethyl 2-amino-3-cyano-4,5-diaryl-1,3-cyclopentenedicarboxylates in moderate to good yields the trans, trans-form isomer being the major product.

scholarly journals Theoretical Insight into the Reversal of Chemoselectivity in Diels-Alder Reactions of α,β-Unsaturated Aldehydes and Ketones Catalyzed by Brønsted and Lewis Acids

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 38-49
Author(s):  
Lakhdar Benhamed ◽  
Sidi Mohamed Mekelleche ◽  
Wafaa Benchouk
Keyword(s):  
Lewis Acids ◽  
Major Product ◽  
Diels Alder ◽  
Unsaturated Ketone ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones ◽  
Theoretical Insight ◽  
Insight Into ◽  
Good Agreement

Experimentally, a reversal of chemoselectivity has been observed in catalyzed Diels–Alder reactions of α,β-unsaturated aldehydes (e.g., (2E)-but-2-enal) and ketones (e.g., 2-hexen-4-one) with cyclopentadiene. Indeed, using the triflimidic Brønsted acid Tf2NH as catalyst, the reaction gave a Diels–Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, the use of tris(pentafluorophenyl)borane B(C6F5)3 bulky Lewis acid as catalyst gave mainly the cycloadduct of α,β-unsaturated aldehyde as a major product. Our aim in the present work is to put in evidence the role of the catalyst in the reversal of the chemoselectivity of the catalyzed Diels–Alder reactions of (2E)-but-2-enal and 2-Hexen-4-one with cyclopentadiene. The calculations were performed at the ωB97XD/6-311G(d,p) level of theory and the solvent effects of dichloromethane were taken into account using the PCM solvation model. The obtained results are in good agreement with experimental outcomes.

scholarly journals Prothrombin fragment 1 X 2 X 3, a major product of prothrombin activation in human plasma.

1986 ◽  
Vol 261 (28) ◽  
pp. 13210-13215 ◽  
Author(s):  
M J Rabiet ◽  
A Blashill ◽  
B Furie ◽  
B C Furie
Keyword(s):  
Human Plasma ◽  
Major Product ◽  
Prothrombin Fragment ◽  
Prothrombin Activation

scholarly journals Hydrogen-Free Deoxygenation of Bio-Oil Model Compounds over Sulfur-Free Polymer Supported Catalysts

2020 ◽  
Vol 7 (1) ◽  
pp. 29-36
Author(s):  
Antonina A. Stepacheva ◽  
Mariia E. Markova ◽  
Yury V. Lugovoy ◽  
Kirill V. Chalov ◽  
Mikhail G. Sulman ◽  
...  
Keyword(s):  
Supercritical Fluids ◽  
Aromatic Compounds ◽  
Supported Catalysts ◽  
Major Product ◽  
Hypercrosslinked Polystyrene ◽  
Model Compounds ◽  
Transportation Fuel ◽  
Novel Approach ◽  
Bio Oil ◽  
Hydrogen Donors

AbstractHydrotreatment of bio-oil oxygen compounds allows the final product to be effectively used as a liquid transportation fuel from biomass. Deoxygenation is considered to be one of the most promising ways for bio-oil upgrading. In the current work, we describe a novel approach for the deoxygenation of bio-oil model compounds (anisole, guaiacol) using supercritical fluids as both the solvent and hydrogen-donors. We estimated the possibility of the use of complex solvent consisting of non-polar n-hexane with low critical points (Tc = 234.5 ºC, Pc = 3.02 MPa) and propanol-2 used as H-donor. The experiments were performed without catalysts and in the presence of noble and transition metals hydrothermally deposited on the polymeric matrix of hypercrosslinked polystyrene (HPS). The experiments showed that the presence of 20 vol. % of propanol-2 in n-hexane results in the highest (up to 99%) conversion of model compounds. When the process was carried out without a catalyst, phenols were found to be a major product yielding up to 95 %. The use of Pd- and Co-containing catalyst yielded 90 % of aromatic compounds (benzene and toluene) while in the presence of Ru and Ni cyclohexane and methylcyclohexane (up to 98 %) were the main products.

Sign in / Sign up

Export Citation Format

Share Document