Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Palladium: A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.Amination: The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Cycloparaffins: Alicyclic hydrocarbons in which three or more of the carbon atoms in each molecule are united in a ring structure and each of the ring carbon atoms is joined to two hydrogen atoms or alkyl groups. The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (From Sax, et al., Hawley's Condensed Chemical Dictionary, 11th ed)Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Alkanes: The generic name for the group of aliphatic hydrocarbons Cn-H2n+2. They are denoted by the suffix -ane. (Grant & Hackh's Chemical Dictionary, 5th ed)Rhodium: Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Epoxy Compounds: Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.Propanols: Isomeric forms and derivatives of PROPANOL (C3H7OH).Gram-Negative Aerobic Bacteria: A large group of aerobic bacteria which show up as pink (negative) when treated by the gram-staining method. This is because the cell walls of gram-negative bacteria are low in peptidoglycan and thus have low affinity for violet stain and high affinity for the pink dye safranine.Phosphines: Inorganic or organic compounds derived from phosphine (PH3) by the replacement of H atoms. (From Grant & Hackh's Chemical Dictionary, 5th ed)Chemistry, Organic: The study of the structure, preparation, properties, and reactions of carbon compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Hydrocarbons, Cyclic: Organic compounds composed exclusively of carbon and hydrogen forming a closed ring that may be either alicyclic or aromatic.Oxygenases: Oxidases that specifically introduce DIOXYGEN-derived oxygen atoms into a variety of organic molecules.Boron: A trace element with the atomic symbol B, atomic number 5, and atomic weight [10.806; 10.821]. Boron-10, an isotope of boron, is used as a neutron absorber in BORON NEUTRON CAPTURE THERAPY.Chemistry Techniques, Synthetic: Methods used for the chemical synthesis of compounds. Included under this heading are laboratory methods used to synthesize a variety of chemicals and drugs.Alcohols: Alkyl compounds containing a hydroxyl group. They are classified according to relation of the carbon atom: primary alcohols, R-CH2OH; secondary alcohols, R2-CHOH; tertiary alcohols, R3-COH. (From Grant & Hackh's Chemical Dictionary, 5th ed)Halogenation: Covalent attachment of HALOGENS to other compounds.Allyl CompoundsCycloaddition Reaction: Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.IminesBoranes: The collective name for the boron hydrides, which are analogous to the alkanes and silanes. Numerous boranes are known. Some have high calorific values and are used in high-energy fuels. (From Grant & Hackh's Chemical Dictionary, 5th ed)Hydrocarbons, Acyclic: Organic compounds composed exclusively of carbon and hydrogen where no carbon atoms join to form a ring structure.Oxidative Coupling: The reaction of two molecular entities via oxidation usually catalyzed by a transition metal compound and involving dioxygen as the oxidant.Organometallic Compounds: A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)KetonesXanthobacter: A genus of gram-negative, aerobic, rod-shaped bacteria found in wet soil containing decaying organic material and in water. Cells tend to be pleomorphic if grown on media containing succinate or coccoid if grown in the presence of an alcohol as the sole carbon source. (From Bergey's Manual of Determinative Bacteriology, 9th ed)HydrocarbonsIpomoea batatas: A plant species of the genus IPOMOEA, family CONVOLVULACEAE. Some cultivars are sweet and edible whereas bitter varieties are a source of SAPONINS. This sweet potato is sometimes referred to as a yam (DIOSCOREA).Vegetables: A food group comprised of EDIBLE PLANTS or their parts.Mallotus Plant: A plant genus of the family EUPHORBIACEAE. Members contain fredelin type TRITERPENES, mallorepine (a cyano-pyridone), and hydrolyzable TANNINS.Citrullus: A plant genus of the family CUCURBITACEAE known for the edible fruit.Daucus carota: A plant species of the family APIACEAE that is widely cultivated for the edible yellow-orange root. The plant has finely divided leaves and flat clusters of small white flowers.beta Carotene: A carotenoid that is a precursor of VITAMIN A. It is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC). (From Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Engewood, CO, 1995.)Polyenes: Hydrocarbons with more than one double bond. They are a reduced form of POLYYNES.PhotochemistryAlkadienes: Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.DelawareChina: A country spanning from central Asia to the Pacific Ocean.GreeceConnecticutAwards and PrizesFormularies as Topic: Works about lists of drugs or collections of recipes, formulas, and prescriptions for the compounding of medicinal preparations. Formularies differ from PHARMACOPOEIAS in that they are less complete, lacking full descriptions of the drugs, their formulations, analytic composition, chemical properties, etc. In hospitals, formularies list all drugs commonly stocked in the hospital pharmacy.Economics, Pharmaceutical: Economic aspects of the fields of pharmacy and pharmacology as they apply to the development and study of medical economics in rational drug therapy and the impact of pharmaceuticals on the cost of medical care. Pharmaceutical economics also includes the economic considerations of the pharmaceutical care delivery system and in drug prescribing, particularly of cost-benefit values. (From J Res Pharm Econ 1989;1(1); PharmacoEcon 1992;1(1))Drug Industry: That segment of commercial enterprise devoted to the design, development, and manufacture of chemical products for use in the diagnosis and treatment of disease, disability, or other dysfunction, or to improve function.Academies and Institutes: Organizations representing specialized fields which are accepted as authoritative; may be non-governmental, university or an independent research organization, e.g., National Academy of Sciences, Brookings Institution, etc.Security Measures: Regulations to assure protection of property and equipment.Legislation, Food: Laws and regulations concerned with industrial processing and marketing of foods.

Phase I and pharmacokinetic study of the topoisomerase II catalytic inhibitor fostriecin. (1/970)

We conducted a phase I and pharmacokinetic study of the topoisomerase II catalytic inhibitor fostriecin. Fostriecin was administered intravenously over 60 min on days 1-5 at 4-week intervals. Dose was escalated from 2 mg m(-2) day(-1) to 20 mg m(-2) day(-1) in 20 patients. Drug pharmacokinetics was analysed with high performance liquid chromatography with UV-detection. Plasma collected during drug administration was tested in vitro for growth inhibition of a teniposide-resistant small-cell lung cancer (SCLC) cell line. The predominant toxicities were elevated liver transaminases (maximum common toxicity criteria (CTC) grade 4) and serum creatinine (maximum CTC grade 2). These showed only a limited increase with increasing doses, often recovered during drug administration and were fully reversible. Duration of elevated alanine-amino transferase (ALT) was dose-limiting in one patient at 20 mg m(-2). Other frequent toxicities were grade 1-2 nausea/vomiting, fever and mild fatigue. Mean fostriecin plasma half-life was 0.36 h (initial; 95% CI, 0-0.76 h) and 1.51 h (terminal; 95% CI, 0.41-2.61 h). A metabolite, most probably dephosphorylated fostriecin, was detected in plasma and urine. No tumour responses were observed, but the plasma concentrations reached in the patients were insufficient to induce significant growth inhibition in vitro. The maximum tolerated dose (MTD) has not been reached, because drug supply was stopped at the 20 mg m(-2) dose level. However, further escalation seems possible and is warranted to achieve potentially effective drug levels. Fostriecin has a short plasma half-life and longer duration of infusion should be considered.  (+info)

RESPONSIVE-TO-ANTAGONIST1, a Menkes/Wilson disease-related copper transporter, is required for ethylene signaling in Arabidopsis. (2/970)

Ethylene is an important regulator of plant growth. We identified an Arabidopsis mutant, responsive-to-antagonist1 (ran1), that shows ethylene phenotypes in response to treatment with trans-cyclooctene, a potent receptor antagonist. Genetic epistasis studies revealed an early requirement for RAN1 in the ethylene pathway. RAN1 was cloned and found to encode a protein with similarity to copper-transporting P-type ATPases, including the human Menkes/Wilson proteins and yeast Ccc2p. Expression of RAN1 complemented the defects of a ccc2delta mutant, demonstrating its function as a copper transporter. Transgenic CaMV 35S::RAN1 plants showed constitutive expression of ethylene responses, due to cosuppression of RAN1. These results provide an in planta demonstration that ethylene signaling requires copper and reveal that RAN1 acts by delivering copper to create functional hormone receptors.  (+info)

Oxidative stress markers in preovulatory follicular fluid in humans. (3/970)

Intensified peroxidation in the Graafian follicle may be a factor compromising the normal development of the oocyte. The aim of this study was to measure concentrations of three oxidative stress markers: conjugated dienes, lipid hydroperoxides and thiobarbituric acid-reactive substances, in preovulatory follicular fluids and sera of 145 women attending an in-vitro fertilization programme, and to correlate these concentrations with pregnancy outcome. Determinations were conducted either with or without an antioxidant (10 microM butylated hydroxytoluene) and an iron chelate (10 microM deferoxamine mesylate) to examine peroxidation associated with the methods used. Concentrations of conjugated dienes, lipid hydroperoxides and thiobarbituric acid-reactive substances in follicular fluid were all significantly lower than those in serum, both in the presence or absence of the antioxidant and iron chelate. These concentrations did not correlate with pregnancy outcome. In conclusion, the intensity of peroxidation in the Graafian follicle is much lower than that in serum. This gradient is the result of the lower rate of initiation of peroxidation in the follicular fluid, suggestive of the presence of efficient antioxidant defence systems in the direct milieu of the oocyte before ovulation. The concentrations of investigated oxidative stress markers in follicular fluid do not reflect the reproductive potential of oocytes.  (+info)

A role for coenzyme M (2-mercaptoethanesulfonic acid) in a bacterial pathway of aliphatic epoxide carboxylation. (4/970)

The bacterial metabolism of short-chain aliphatic alkenes occurs via oxidation to epoxyalkanes followed by carboxylation to beta-ketoacids. Epoxyalkane carboxylation requires four enzymes (components I-IV), NADPH, NAD(+), and a previously unidentified nucleophilic thiol. In the present work, coenzyme M (2-mercaptoethanesulfonic acid), a compound previously found only in the methanogenic Archaea where it serves as a methyl group carrier and activator, has been identified as the thiol and central cofactor of aliphatic epoxide carboxylation in the Gram-negative bacterium Xanthobacter strain Py2. Component I catalyzed the addition of coenzyme M to epoxypropane to form a beta-hydroxythioether, 2-(2-hydroxypropylthio)ethanesulfonate. Components III and IV catalyzed the NAD(+)-dependent stereoselective dehydrogenation of R- and S-enantiomers of 2-(2-hydroxypropylthio)ethanesulfonate to form 2-(2-ketopropylthio)ethanesulfonate. Component II catalyzed the NADPH-dependent cleavage and carboxylation of the beta-ketothioether to form acetoacetate and coenzyme M. These findings evince a newfound versatility for coenzyme M as a carrier and activator of alkyl groups longer in chain-length than methane, a function for coenzyme M in a catabolic pathway of hydrocarbon oxidation, and the presence of coenzyme M in the bacterial domain of the phylogenetic tree. These results serve to unify bacterial and Archaeal metabolism further and showcase diverse biological functions for an elegantly simple organic molecule.  (+info)

Importance of the beta12-beta13 loop in protein phosphatase-1 catalytic subunit for inhibition by toxins and mammalian protein inhibitors. (5/970)

Type-1 protein serine/threonine phosphatases (PP1) are uniquely inhibited by the mammalian proteins, inhibitor-1 (I-1), inhibitor-2 (I-2), and nuclear inhibitor of PP1 (NIPP-1). In addition, several natural compounds inhibit both PP1 and the type-2 phosphatase, PP2A. Deletion of C-terminal sequences that included the beta12-beta13 loop attenuated the inhibition of the resulting PP1alpha catalytic core by I-1, I-2, NIPP-1, and several toxins, including tautomycin, microcystin-LR, calyculin A, and okadaic acid. Substitution of C-terminal sequences from the PP2A catalytic subunit produced a chimeric enzyme, CRHM2, that was inhibited by toxins with dose-response characteristics of PP1 and not PP2A. However, CRHM2 was insensitive to the PP1-specific inhibitors, I-1, I-2, and NIPP-1. The anticancer compound, fostriecin, differed from other phosphatase inhibitors in that it inhibited wild-type PP1alpha, the PP1alpha catalytic core, and CRHM2 with identical IC(50). Binding of wild-type and mutant phosphatases to immobilized microcystin-LR, NIPP-1, and I-2 established that the beta12-beta13 loop was essential for the association of PP1 with toxins and the protein inhibitors. These studies point to the importance of the beta12-beta13 loop structure and conformation for the control of PP1 functions by toxins and endogenous proteins.  (+info)

Degradation of trichloroethene by a linear-plasmid-encoded alkene monooxygenase in Rhodococcus corallinus (Nocardia corallina) B-276. (6/970)

Rhodococcus corallinus (formerly Nocardia corallina) B-276, isolated with propene as sole carbon and energy source, is able to oxidize trichloroethene (TCE). Glucose- or propene-grown R. corallinus B-276 cells exhibited no difference in TCE degradation efficiency. TCE degradation was found to be growth-phase-dependent and maximum rates were monitored with stationary-phase cells. K(m) and Vmax values for TCE degradation of R. corallinus B-276 grown in nutrient broth medium in the presence of glucose were 187 microM and 2.4 nmol min-1 (mg protein)-1, respectively. Escherichia coli recombinants harbouring and expressing the alkene monooxygenase genes of R. corallinus B-276 exhibited the ability to degrade TCE. This result provides clear evidence that the alkene monooxygenase of R. corallinus B-276 catalyses TCE oxidation. R. corallinus B-276 was shown to contain four linear plasmids, pNC10 (70 kb), pNC20 (85 kb), pNC30 (185 kb) and pNC40 (235 kb). The observation that pNC30-deficient strains had lost the ability to grow on propene suggested that the genes of the propene degradation pathway are encoded by the linear plasmid pNC30. Southern blot analysis with cloned alkene monooxygenase genes from R. corallinus B-276 revealed a positive hybridization signal with the linear plasmid pNC30. This result clearly shows that the alkene monooxygenase is encoded by the linear plasmid pNC30. Eleven short-chain-alkene-oxidizing strains were screened for the presence of linear plasmids. Among these, four propene-oxidizing Rhodococcus strains and one ethene-oxidizing Mycobacterium strain were found to contain linear megaplasmids. Southern blot analysis with the alkene monooxygenase revealed positive signals with linear plasmids of two propene-oxidizing Rhodococcus ruber strains. These results indicate that homologous alkene monooxygenases are encoded by linear plasmids in R. ruber strains.  (+info)

Characterization of the gene cluster involved in isoprene metabolism in Rhodococcus sp. strain AD45. (7/970)

The genes involved in isoprene (2-methyl-1,3-butadiene) utilization in Rhodococcus sp. strain AD45 were cloned and characterized. Sequence analysis of an 8.5-kb DNA fragment showed the presence of 10 genes of which 2 encoded enzymes which were previously found to be involved in isoprene degradation: a glutathione S-transferase with activity towards 1,2-epoxy-2-methyl-3-butene (isoI) and a 1-hydroxy-2-glutathionyl-2-methyl-3-butene dehydrogenase (isoH). Furthermore, a gene encoding a second glutathione S-transferase was identified (isoJ). The isoJ gene was overexpressed in Escherichia coli and was found to have activity with 1-chloro-2,4-dinitrobenzene and 3,4-dichloro-1-nitrobenzene but not with 1, 2-epoxy-2-methyl-3-butene. Downstream of isoJ, six genes (isoABCDEF) were found; these genes encoded a putative alkene monooxygenase that showed high similarity to components of the alkene monooxygenase from Xanthobacter sp. strain Py2 and other multicomponent monooxygenases. The deduced amino acid sequence encoded by an additional gene (isoG) showed significant similarity with that of alpha-methylacyl-coenzyme A racemase. The results are in agreement with a catabolic route for isoprene involving epoxidation by a monooxygenase, conjugation to glutathione, and oxidation of the hydroxyl group to a carboxylate. Metabolism may proceed by fatty acid oxidation after removal of glutathione by a still-unknown mechanism.  (+info)

Porcine kidney microsomal cysteine S-conjugate N-acetyltransferase-catalyzed N-acetylation of haloalkene-derived cysteine S-conjugates. (8/970)

N-Acetylation of xenobiotic-derived cysteine S-conjugates is a key step in the mercapturic acid pathway. The aim of this study was to investigate the N-acetylation of haloalkene-derived S-haloalkyl and S-haloalkenyl cysteine S-conjugates by porcine kidney cysteine S-conjugate N-acetyltransferase (NAcT). A radioactive assay for the quantification of NAcT activity was developed as a new method for partial purification of the enzyme, which was necessitated by the substantial loss of activity during the immunoaffinity chromatography method. 3-[(3-Cholamidopropyl)dimethylammonio]-1-propane-sulfonate, rather than N,N-bis[3-gluconamidopropyl]deoxycholamide, was used to solubilize the NAcT from porcine kidney microsomes in the revised procedure. The partially purified NAcT was free of detectable aminoacylase activity. Although low acetyl-coenzyme A hydrolase activity was observed, its effect on the assay was minimized by addition of excess acetyl-coenzyme A in the NAcT assay mixture. Attempts to separate the residual hydrolase activity from NAcT by different chromatographic procedures were either unsuccessful or lead to inactivation of NAcT. Most of the cysteine S-conjugates studied were N-acetylated by NAcT. Although the apparent K(m) values for the cysteine S-conjugates studied differed by a factor of approximately 2.5 (124-302 microM), a greater than 15-fold difference in the apparent V(max) (0.75-15.6 nmol/h) and V(max)/K(m) (0.008-0.126 x 10(-3) l h(-1)) values was observed. These data show that a range of haloalkene-derived cysteine S-conjugates serve as substrates for pig kidney NAcT. The significant differences in cytotoxicity of these conjugates may be a result of more variable deacetylation rates of the corresponding mercapturates.  (+info)

  • An Improved Protocol For the Oxidative Cleavage of Alkynes, Alkenes, a" by A. Vijay Kumar, Prakash Reddy et al. (
  • An Improved Protocol For the Oxidative Cleavage of Alkynes, Alkenes, and Diols with Recyclable Ru/C," Synlett , Georg Thieme Verlag, Jan 2009. (
  • Internal alkenes were inert under these conditions, but Yoshikazo Kitano of the Tokyo University of Agriculture and Technology effected ( Synthesis 2014 , 46 , 1455. (
  • Nickel/NHC-Catalyzed Asymmetric C-H Alkylation of Fluoroarenes with Alkenes: Synthesis of Enantioenriched Fluorotetralins. (
  • Gem-Dibromocyclopropanes are versatile intermediates in the synthesis of many natural products and are usually prepared via a two-phased catalyzed dihalocyclopropanation of alkenes. (
  • The enzyme indicated is a special kind, known as flavoprotein in reaction) Dehydrogenation of alkanes is not a practical laboratory synthesis for the vast majority of alkenes. (
  • The effect of Fe content on FeMn/MgO catalysts for light alkenes synthesis through CO hydrogenation was investigated. (
  • The synthesis of these cage alkenes are summarised in Scheme 7.1. (
  • Synthesis of the cage alkene 125 by the cycloaddition of 9 to 118 failed. (
  • The synthesis of cage alkenes from 4-isopropylidenepentacyclo[,6.03,10.05,undecane-8,11-dione (23) did not meet with much success (Scheme 7.4). (
  • Efficient synthesis of carboxylic acids from alkenes and diols employing Ru/C-based recyclable catalytic system is reported with good to excellent yields. (
  • Direct and indirect roles of alkenes cannot be ignored, and this book will aim to include new findings in the alkenes (olefins) area, focusing on the industrial aspects of alkenes (olefins) production, separation, purification, kinetic, mechanism, wastewater treatment, etc. (
  • Alkenes (or olefins, olefines in old-fashioned parlance) - unsaturated hydrocarbons that contain one or more carbon-carbon double bonds. (
  • The physical properties of alkenes: the dipole moments of most alkenes are quite small, a methyl group releases electrons to a double bond in much the same way that it releases electrons to the positively charged carbon of a carbocation-by an inductive effect and by hyperconjugation. (
  • abstract = "An efficient method for C7-position-selective alkenylation of N-substituted indolines with alkenes is reported. (
  • Some natural sources of alkenes are terpenes, ethylene, food containing Vitamin A and β-carotene. (
  • If you're a chemist, you have a keen sense of the importance of the alkene," Erik Sorensen, the Arthur Allan Patchett Professor in Organic Chemistry at Princeton and corresponding author. (
  • (
  • Alkenes, and in particular terminal alkenes, are readily prepared (e.g. (
  • Background: OleTJE oxidatively decarboxylates fatty acids to produce terminal alkenes. (
  • The regioselective hydroboration of aliphatic internal alkenes remains a great challenge. (
  • Reported herein is an iridium-catalyzed hydroboration of aliphatic internal alkenes, providing distal-borylated products in good to excellent yields with high regioselectivity (up to 99:1). (
  • Chemists at Princeton have developed a new chemical method to introduce valuable alkenes into simple hydrocarbon molecules, a transformation known as dehydrogenation, which is found in important processes such as the biosynthesis of essential fatty acids in the body and the commercial production of detergents. (
  • efficient conditions for the Wacker oxidation of a terminal alkene 6 to the methyl ketone 13 . (
  • ClO 4 - to five trans alkenes (2-butene, 2-pentene, 4-methyl-2-pentene, 3-octene, 5-decene) and four cis alkenes (2-pentene, 2-hexene, 2-heptene, 5-decene) gave in each case a mixture of mono- and bisadducts in which the configuration of the alkene was retained. (
  • This kind of image (Acid Catalyzed Hydration Of 2 Methyl 2 butene Beautiful Alkene) above can be classed using:submitted by means of admin in 2019-03-15 15:32:52. (
  • In these additions to alkenes, cis alkenes gave predominantly bisadducts, while trans alkenes (except for trans-2-butene) gave predominantly monoadducts. (
  • Compared with the specialized membrane applied to separate one type of mixture, the membranes that are able to selectively separate diverse alkane/alkene mixtures are more valuable in chemical and petroleum industry. (
  • Zaitsev's rule is an empirical one and summarizes the results of numerous experiments in which alkene mixtures were produced by i? (
  • In the NMR spectra of (E)- and (Z)-(5-thianthreniumyl)alkenes, the alkenyl proton of Z isomers always appeared at a lower field (0.8-1.0 ppm) than that of E isomers. (
  • As noted by queenofbabes, this difference in chemical reactivity is due to the fact that benzen's electronic structure (i.e. it's molecular orbitals) is very much different than the electronic structure of typical alkenes. (