Showing papers on "Double bond published in 1970"
172 citations
131 citations
TL;DR: Three parameters involved in the binding of substrate to linoleate isomerase of Butyrivibrio fibrisolvens have been identified and two chelators, o-phenanthroline and EDTA, were identified as reversible inhibitors of the enzyme.
130 citations
TL;DR: It is concluded that the resistance of unsaturated or branched acids is due to steric hindrance during the formation of the activated complex, and the saturated C4-chain seems to be optimally adaptable to the enzyme.
85 citations
TL;DR: In this paper, the authors derived the magnetic anisotropy screening and the electric field screening effect of the CO group in a complete series of monoketo-androstanes, including the values of the anisotropies of the CO double bond and of K, a parameter descriptive of the electric screening effect.
84 citations
73 citations
TL;DR: In this article, the mechanisms of double-bond migration and the exchange of D2 with the hydrogen atoms of small cyclic olefins (methylenecyclobutane, methylenecylclopentane, cyclopentene, 3-methylcyclopentenes, cyclohexene, and bicyclo-(2,2,1)-hepta-2, 5-diene) were investigated over a pure alumina catalyst.
Abstract: The mechanisms of double-bond migration and the exchange of D2 with the hydrogen atoms of small cyclic olefins (methylenecyclobutane, methylenecyclopentane, cyclopentene, 3-methylcyclopentene, cyclohexene, and bicyclo-(2,2,1)-hepta-2, 5-diene) were investigated over a pure alumina catalyst. At temperatures below 100°, only those hydrogen atoms which were initially vinyl, or which could become vinyl by isomerization of the olefin, underwent exchange. A primary kinetic isotope effect of about 2.8 was found, indicating that cleavage of the C—H bond was probably the slow step in the exchange reaction. Rapid intermolecular scrambling of all vinyl hydrogen atoms was observed, and the presence of the olefins greatly reduced the usually fast rate of H2+ D2 equilibration.
Double-bond migration below 100° was sensitive to the geometry of the olefin. Only molecules having a three carbon chain, including the double bond, which could appear concave when viewed from outside the molecule underwent isomerization; those which did not fulfill this requirement did not isomerize. Nearly pure 1,2-cyclopentene-d2 could be prepared, suggesting a dissociative mechanism for the exchange reaction. Hence, exchange and double-bond migration are independent processes, although both reactions may have involved the same sites and may have had a common intermediate. Poisoning experiments using radioactive CO2 indicated an active site density of about 1.4 × 1013 cm–2 for the exchange reaction after 530° pretreatment.
63 citations
Patent•
17 Dec 1970TL;DR: In this article, the authors discuss the role of ORGANIC POLYMERS to solve inorGANIC SURFACES in the form of agents, agents, and agents.
Abstract: ORGANOSILICON COMPOUNDS OF THE FORMULA (*SI-Q-N(+)(-R''M)-Z-C(-R")=CH2) Y(-) IN WHICH Q IS A DIAVALENT HYDROCARBON RADICAL OR A DIVALENT HYDROCARBON RADICAL CONTAINING OXYGEN IN THE FORM OF -CO-C-, -COO-C-, -CO-, OR >C(-OH)- GROUPS OR NITROGEN IN THE FORM OF >N-R" GROUPS, Z IS A DIVALENT ORGANIC RADICAL HAVING A DOUBLE BOND CONJUGATED WITH THE -C(-R")=CH2 AS COUPLING AGENTS FOR PROMOTING THE ADHESION OF ORGANIC POLYMERS TO SOLID INORGANIC SURFACES. CH=C(-CH3)-CH=CH2) BR(-) ((C3H7-O)3-SI-(CH2)2-(1,4-PHENYLENE)-N(+)(-CH3)2-CH2- MOIETY, Z BEING BONDED TO THE NITROGEN ATOM BY A C-N BOND, R'' IS INDEPENDENTLY SELECTED FROM THE GROUP CONSISTING OF THE HYDROGEN ATOM, LOWER ALKYL RADICAL ORR A HETEROCYCLIC ORGANIC COMPOUND CONTAINING THE NITROGEN ATOM AS A RING MEMBER, M IS AN INTEGGER OF 1 ORR 2, R" IS THE HYDROGEN ATOM OR A LOWER ALKYL RADICAL, AND Y IS AN ACID ANION, ARE DISCLOSED. THE COMPOUNDS, FOR EXAMPLE
57 citations
TL;DR: The synthesis of 2-vinyl-3,4,5,6,6-tetrahydrobenzaldehyde is described in this article, which equilibrates above 70° with its valence isomer 4,5-Tetramethylene-2H-pyran as can be shown by cis-trans-isomerization of the double bond in selectively deuterated.
Abstract: The synthesis of 2-vinyl-3,4,5,6-tetrahydrobenzaldehyde (10) is described. This compound equilibrates above 70° with its valence isomer 4,5-tetramethylene-2H-pyran (11) as can be shown by cis-trans-isomerization of the double bond in selectively deuterated 10. The unstable 2H-pyran 11 can be trapped as tetracyanoethylene adduct 12.
Gas phase pyrolysis of 6-oxabicyclo [3.1.0] hex-2-ene (18) at 400°C leads to cis-penta-2, 4-dienal (19) in fair yield.
55 citations
TL;DR: A soluble (105,000 x g supernatant) enzyme preparation from a pseudomonad has been obtained which catalyzes the interconversion of oleic acid and 10d-hydroxystearic acid, compatible with a mechanism involving a hydration of the double bond.
Patent•
26 Jan 1970TL;DR: Olefin reaction catalysms are converted by contact with MAGNESIUM OXIDE prior to the conversion as discussed by the authors, and are pre-referred to as OLEFIN as discussed by the authors.
Abstract: OLEFINS ARE CONVERTED BY CONTACTING A MIXTURE OF AT LEAST TWO DOUBLE BOND ISOMERS WITH AN OLEFIN REACTION CATALYST. OLEFINS ARE PRETREATED BY CONTACT WITH MAGNESIUM OXIDE PRIOR TO THE CONVERSION.
TL;DR: In this article, the π-allene-metal linkage in compounds of tetramethylallene (TMA) and 1,1-dimethylallenes (1, 1-DMA) with platinum (II) and rhodium (I) has been investigated.
TL;DR: In this paper, the phosphorus-carbon bond of alkylidene phosphoranes is studied with semi-empirical molecular orbital calculations, and the potential surface for a concerted intramolecular hydrogen migration leads to a pentavalent phosphorus derivative.
Abstract: The phosphorus-carbon bond of phosphonium ylides is studied with semiempirical molecular orbital calculations. The primary effect of the inclusion of 3d orbitals on phosphorus is the anticipated electron transfer from the ylide carbon to the 3d orbitals, with an accompanying increase in P-C bond order. A novel effect of some significance is the hyperconjugative a-type interaction of CHZ orbitals in a model H3PCHz with a P 3d orbital of the appropriate symmetry. Intermolecular and intramolecular mechanisms for proton transfer in (CH3)3PCH2 are studied. A concerted hydrogen switch involving two molecules is calculated to possess a high activation energy. The potential surface for a concerted intramolecular hydrogen migration leads to a transition state best described as a pentavalent phosphorus derivative. Carbon diradicals should be stabilized by intervening phosphorus or other second-row atoms. This type of stabilization is studied for a hypothetical CH2PR3CH2. Such species are potential singlet states and should possess barriers to rotation of CHZ groups but not of the PRa moiety. hosphonium ylides or alkylidene phosphoranes, P whose electronic structure is commonly described as a resonance hybrid 1, derive much of their current \ + -/ \ / -P-c /P=c\ / \ 1 importance from the synthetic utility of the Wittig reaction. -P=C \ ’ \R2 R4 /R1 + o=c\ /R3 + \ R, \c=c /R3 -P=O + / &’ \R, The ylides are fascinating compounds in their own right, exhibiting a remarkable variety of structural types exemplified by the species 2-5. 3-6 The resonance hybrid formulation 1 implies the verifiable existence of double bond character and the less verifiable concomitant participation of phosphorus 3d orbitals in bonding. The presence of partial double bond character is indicated by P-C interatomic distance~’-’~ of 1.66-1.74 A, intermediate between an (1) G. Wittig and G. Geissler, Jusfus Liebigs Ann. Chem., 580, 44 (1953), and subsequent papers. (2) An excellent source of information on phosphonium ylides is A. W. Johnson, “Ylid Chemistry,” Academic Press, New York, N. Y., 1966. (3) F. Rarnirez, N. B. Desai, B. Hansen, and N. McKelvie, J . Amer. Chem. Soc., 83,3539 (1961). (4) F. Ramirez and S. Levy, ibid., 79,67 (1957). ( 5 ) C. N. Matthews, J. S. Driscoll, and G. H. Birum, Chem. Com(6) C. N. Matthews and G. H. Biruni, Tefruhedron Lef t . , 5707 mun., 736 (1966). (1966); Accounts Chem. Res . , 2 , 373 (1969). \ / 7p=c=p\ 2
TL;DR: In this paper, the products from the individual reactions of allylmagnesium bromide with 2-styrylpyridine, with 4-stylryl-polycyclic double bond, and with α-allylbenzhydrylaniline, rrespectively, were examined, in order to test the possible role of electron transfer processes both in the addition and elimination steps of Grignard reagent-anil interactions.
TL;DR: In this paper, the three main components of the mixture of corynomycolic acids (α-branched, β-hydroxy acids of the general formula R1-CHOH-CHR2-COOH) isolated from a strain of Corynebacterium hofmanii are:
Abstract: The three main components of the mixture of corynomycolic acids (α-branched, β-hydroxy acids of the general formula R1—CHOH—CHR2—COOH) isolated from a strain of Corynebacterium hofmanii are:
C32H64O3 (corynomycolic acid); C34H66O3 (corynomycolenic acids); C36H68O3 (corynomycoldienic acid).
By thin-layer chromatography on silver nitrate-impregnated Silicagel G, we were able to separate the hydroxy acids having 0, 1 or 2 double bonds. The pyrolytic chromatography of their methyl esters indicates that the mono-unsaturated acids form a mixture of C34-acids containing the double bond either in the main chain or in the side chain; the di-unsaturated acid fraction is constituted solely by a C36-acid with a double bond in each fragment arising from pyrolysis.
By oxidative cleavage, we find that the position of the double bond is 9, 10 (as in oleic acid). According to the nature of the main chain (aldehyde fragment of pyrolysis) and of the side chains (ester fragment of pyrolysis), some suggestions are made about the selective use of fatty acids in the biosynthesis of corynomycolic acids.
TL;DR: The results of incubations of the cis- and trans-9,10-epoxystearic acids in water enriched with respect to 18O indicated that the enzyme-catalyzed hydration of the epoxide functions occurred with stereospecific incorporation of the oxygen of water at carbon atom 10.
TL;DR: In this article, the absolute structure of decumbin was presented as [II] by the following evidences: the configuration about C4 was determined as (S) by the benzoate rule on the tetrahydromonoketone (21).
Abstract: From the mycelium of Ascochyta imperfecta decumbin, C16H24O4, mp 203°C, was obtained in one percent yield.The absolute structure of decumbin was presented as [II] by the following evidences: The configuration about C4 was determined as (S) by the benzoate rule on the tetrahydromonoketone (21). The hydroxyl at C7 is α, because tetrahydrodecumbin (23) showed no intramolecular hydrogen bond, while its C7 epimer (24) did. Ring juncture was determined by ORD of a five membered ketone (16). Two double bonds were found to be trans from IR data. The stereochemistry of decumbin monoepoxide (7), tetrahydropyrans (12 and 13) was also studied. Plant tests of the twenty derivatives of decumbin on lucerne and rape revealed that the growth inhibition activity has close relation with the presence of double bond in the thirteen membered lactone ring.
TL;DR: A series of organotitanium compounds of structure (π-C 5 H 5 ) 2 Ti(R)Cl was prepared, where the R ligand was attached by a σ-Ti C bond as discussed by the authors.
TL;DR: It was concluded that the presence of a Delta(9)cis double bond is necessary for growth and the need for a specific chain length or a specific number of double bonds, or for both, is more flexible.
Abstract: A fatty acid Δ9-desaturase mutant of yeast was analyzed to establish the specificity of the fatty acid structural requirement. Several double-bond-containing and substituted fatty acids were tested. It was concluded that the presence of a Δ9cis double bond is necessary for growth. The need for a specific chain length or a specific number of double bonds, or for both, is more flexible. Tracer-containing 16:1Δ9cis, 18:1Δ9cis, 18:2Δ9,12cis,cis and 18:3Δ9,12,15 all cis revealed that each of these growth-supporting components, once taken up, was not converted into other fatty acids. Concentration effects on doubling time were also considered.
TL;DR: In this paper, the 1,3-dipole cycloaddition of nitrile oxides with tropone yields a mixture of at least 8 products, the structures of which are based on spectral and chemical evidence.
TL;DR: Aluminium hydride, tri-t-butoxy-aluminium hydroxide, and sodium borohydride have been shown to reduce the carbonyl group, double bond, and double bond of a conjugated cyclopentenone.
Abstract: Aluminium hydride, lithium tri-t-butoxy-aluminium hydride, and sodium borohydride reduce specifically the carbonyl group, the double bond, and both the carbonyl group and the double bond, respectively, of a conjugated cyclopentenone, while lithium aluminium hydride gives all three products in varying amounts depending on the reaction conditions.
TL;DR: The structure of 1,5-cyclooctadienebis (iron tetracarbonyl) has been determined from a three-dimensional X-ray analysis as mentioned in this paper, which was solved by automatic phase determination through symbolic addition procedure, and successive Fourier-synthesis.
TL;DR: In this paper, the double-bond-system-compliant compounds containing the double bond system (Doppelbindung) react with aryl isocyanates under formation of different products depending on reaction conditions and substituents on the heterodienes.
Abstract: Verbindungen mit dem Doppelbindungssystem CNCN bilden mit Arylisocyanaten in Abhangigkeit von den Reaktionsbedingungen und Substituenten am Heterodien verschiedene cyclische Produkte: 1:1-Addukte mit Tetrahydro-s-triazin-Struktur (10), 2:1-Addukte (Isocyanat : CN-Komponente) mit Hexahydro-s-triazin-Struktur (11) und Folgeprodukte der Spaltung intermediar entstehender Cycloaddukte mit Tetrahydro-s-triazin-Struktur (13, 18, 19, 20 und 21).
Reactions of Aryl Isocyanates with Compounds Containing the Double Bond System CNCN
Compounds containing the double bond system CNCN react with aryl isocyanates under formation of different products depending on the reaction conditions and substituents on the heterodienes: l : l-adducts with tetrahydro-s-triazine structure (10), 2:l-adducts (isocyanate : CN component) with hexahydro-s-triazine structure (11), and products of a dissociation of intermediate cycloadducts followed by repeated reaction with isocyanate which also have tetrahydro-s-triazine structure (13, 18, 19, 20 and 21).
TL;DR: In this paper, a method combining thermal fragmentation and mass spectrometry for the determination of the position of double bonds in an unsaturated ester is presented, where the positions of the deuterium atoms in the original ester are revealed by the deutetium content of its fragments as determined by mass-spectrometry.
Abstract: A method combining thermal fragmentation and mass spectrometry for the determination of the position of double bonds in an unsaturated ester is presented. The thermal fragmentation of methyl esters of deuterated long chain carboxylic acids yields a homologous series of olefins plus a homologous series of unsaturated esters. The positions of the deuterium atoms in the original ester are revealed by the deuterium content of its fragments as determined by mass spectrometry. Therefore, the positions of double bonds of a polyunsaturated acid can be determined by pyrolysis after saturation by deuterium. The structures of the unsaturated fragments are ascertained by mass spectrometric method, and the formation of the ion [M – 32] in the mass spectrometric fragmentation of unsaturated methyl esters is studied by means of deuterium labeling.
TL;DR: In this paper, the isomerization reaction of methyl linoleate and methyl linolenate with potassium t-butoxide has been investigated and the relationships between these analyses and observed differences in absorptivities by UV spectrometry are discussed.
Abstract: The isomerization reaction of methyl linoleate and methyl linolenate with potassiumt-butoxide has been investigated. The compositions of the reaction products formed at three temperatures have been determined and the relationships between these analyses and observed differences in absorptivities by UV spectrometry are discussed. Conclusions concerning the reaction mechanisms are based on compositional analysis and results of experiments using radioactive or stable isotope labeled reagent. Double bonds in molecules which are not conjugated during the reaction retain the originalcis configuration. The double bond in the Δ12 position is the most susceptible to positional isomerization to form the conjugated system. With the diene, this selectivity is small, while with the triene, the shifting of the Δ12 bond is the preponderant initial reaction. Isotopic experiments yielded direct evidence for the postulated carbanion mechanism of reaction. An activated methylene group is generally required for the formation of the carbanion. While the UV spectra of the reaction products formed from methyl linolenate at 140 C showed no peak in the diene region, 34% conjugated diene-triene was present. The intact conjugated systems can migrate when the reaction is sufficiently energentic to produce conjugated trienes with double bonds other than the 10, 12, 14 system. The conjugation of triene is a stepwise reaction through the conjugated dienetriene.