- Disparate Reactivity of 4-Tricyclic Iodide and Chloride in the SRN1 Reaction; Bridgehead revisited
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The remarkably facile SRN1 reaction of 4-tricyclil iodide and the near inertia of 4-tricyclyl chloride under the same conditions are compared with the reactivity of other bridgehead compounds; the nature of the SRN1 reaction for aliphatic substrates is discussed.
- Santiago, Ana N.,Morris, David G.,Rossi, Roberto A.
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- Oxidation of α-pinene by atmospheric oxygen in the supercritical CO2-ethyl acetate system in the presence of Co(II) complexes
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The reactivity of monoterpene α-pinene in a flow reactor in the presence of cobalt catalyst in a complex supercritical solvent consisting of CO2 and ethyl acetate is studied over the temperature range of 190-320°C and a pressure range of 110-125 atm. It was found that the main isomerization products include compounds with bicyclo[2.2.1]heptane and p-menthane backbones; the reaction is accompanied by partial racemization. The formation of oxidation products is observed in the presence of air, with epoxydation rather than allylic oxidation being the predominant process at the first stage. The oxidized products (campholenic aldehyde, verbenone, pinocamphone) are shown to be formed with a high enantioselectivity; the formation of acetoxylation products is observed at temperatures above 200°C.
- Anikeev,Ilina,Kurbakova,Nefedov,Volcho,Salakhutdinov
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experimental part
p. 190 - 195
(2012/03/12)
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- Selective vapour-phase α-pinene isomerization to camphene over gold-on-alumina catalyst
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The vapour-phase isomerization of α-pinene for the first time was studied over a supported Au catalyst. α-pinene was isomerized to camphene over the 2.2% Au/γ-Al2O3 catalyst at 463-483 K using a solution of the reagent in n-octane as the initial reaction mixture and H2 or N2 as a carrier gas. Under these conditions, the selectivity to camphene reaches 60-80% at 99.9% conversion of α-pinene. The reaction is found to be first-order with respect to α-pinene, the apparent activation energy being similar to that observed with the conventional TiO2 catalyst. The prominent catalyst deactivation has been observed at increased α-pinene concentrations in the inlet reaction mixture (≥4 vol% in n-octane solution). According to HRTEM and TPO results, the deactivated catalyst contains the carbonaceous deposits that may block the catalyst surface. Almost complete regeneration was done in flowing O2 at temperature up to 923 K required to totally eliminate the coke deposits.
- Simakova,Solkina, Yu.S.,Moroz,Simakova,Reshetnikov,Prosvirin,Bukhtiyarov,Parmon,Murzin, D.Yu.
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experimental part
p. 136 - 143
(2010/11/18)
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- Thermal transformation of monoterpenes within thionin-supported zeolite Na-Y. Acid-catalyzed or electron transfer-induced?
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Several monoterpenes (monocyclic, bicyclic or acyclic) isomerize and finally transform to p-cymene in the dark upon loading within thionin-supported zeolite Na-Y. The same reactions occur in Na-Y dried under the same conditions as thionin/Na-Y. It is postulated that the thermal treatment of Na-Y generates 'electron holes' (probably acidic sites). The transformation of monoterpenes occurs more likely via an electron transfer-induced reaction subordinated to the occurrence of the acidic sites. The radical cation of the more thermodynamically stable monoterpene, α-terpinene, eventually dehydrogenates to p-cymene. For comparison, the same reactions were performed within methyl viologen-supported Na-Y. Copyright
- Stratakis, Manolis,Stavroulakis, Manolis,Sofikiti, Nikoletta
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- Dehydration of Alcohols Catalysed by Heteropolyacids Supported on Silica
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Keggin type heteropolyacids supported on silica efficiently dehydrate secondary and tertiary alcohols under mild conditions and in good yields to afford the correspondent alkenes.
- Alesso, Elba,Torviso, Rosario,Finkielsztein, Liliana,Lantano, Beatriz,Moltrasio, Graciela,Aguirre, Jose,Vazquez, Patricia,Pizzio, Luis,Caceres, Carmen,Blanco, Mirta,Thomas, Horacio
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p. 1232 - 1245
(2007/10/03)
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- Process for the production of 1,4,7,10-tetraazacyclododecane and its derivatives
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A process for the production of 1,4,7,10-tetraazacyclododecane (cyclene) and its derivatives on an industrial scale comprises cyclotetramerizing of benzylaziridine that is produced in situ.
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- Liquid-phase isomerization of α-pinene on a natural clinoptilolite
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The liquid-phase isomerization of α-pinene on a suspended powder (50-100 μm) of a natural clinoptilolite is studied. It is found that thermoevacuation at 500°C decreases the catalyst's activity and selectivity. The surface acidity decreases, whereas the surface concentration of Fe2+ ions increases. The reaction mechanism is proposed.
- Allakhverdiev,Sokolova,Gunduz,Kul'kova
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p. 1647 - 1650
(2007/10/03)
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- Reaction of Hydrazones with Methoxy(tosyloxy)iodobenzene (MTIB): Tosylate Formation under Oxidative Conditions
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Treatment of aromatic hydrazones 1 containing electron-withdrawing, reduction sensitive substituents with MTIB gives the corresponding tosylates 2 in high yield. When the tosylate is particularly reactive the thermodynamically more stable methyl ether 3 is isolated. Analogous reactions with DAIB give acetates 4 in high yield. Dialkyl hydrazones give olefinic products (e.g. 7 and 8). (+)-Camphor hydrazone 1k with either MTIB or DAIB gives both camphene 12 (major product) and tricyclene 11 (minor product) suggesting that a carbene pathway accounts for some of the material formed in these oxidations.
- Ramsden, Christopher A.,Rose, Helen L.
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- Catalytic Transformation of camphene over Aluminophosphate-based Molecular Sieves
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The catalytic transformation of camphene over AlPO4-11, SAPO-5, SAPO-11, VAPO-5, VAPO-11, CoAPO-5, CoAPO-11, NAPO-5, NAPO-11, ZAPO-5 and ZAPO-11 in the vapour phase has been studied.The products formed are tricyclene, bornylene and monocyclic terpenes.The
- Elangovan, S. P.,Arabindoo, Banumathi,Krishnasamy, V.,Murugesan, V.
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p. 4471 - 4476
(2007/10/03)
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- Synthesis, Characterization, and Catalytic Activity of NAPO-5 and NAPO-11
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Nickel-substituted aluminophosphate molecular sieves (NAPO-5 and NAPO-11) were synthesized hydrothermally using triethylamine and dipropylamine as templates.Structures were confirmed by X-ray powder pattern, and unit cell parameters calculated by a standard least square refinement technique.The isomorphous substitution of nickel in the aluminophosphate framework is evidenced by the considerable increase in unit cell volume compared to unsubstituted AlPO4-5 and AlPO4-11.In addition, electron spin resonance and diffuse reflectance spectra were carried out to produce supporting evidence for the isomorphous substitution of nickel.Acidity was determined by TPD-TGA method which shows two types of acid sites.Symmetry and asymmetry vibrations were obtained from infrared spectra.Chemical analysis by ICP and BET surface area are also reportedd.The physicochemical properties of the catalysts were correlated towards isomerization of camphene at various (WHSV)-1 values and temperatures.The products formed are tricyclene and 2-bornene and the selective formation of tricyclene was achieved over, these catalysts.
- Elangovan, Shanmugam P.,Krishnasamy, Vengaimuthu,Murugesan, Velayutham
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p. 3659 - 3664
(2007/10/03)
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- Reactions of Thianthrene Cation Radical with Acyclic and Cyclic Alcohols
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Thianthrene cation radical perchlorate (Th(.+)*ClO4(-)) reacted readily with cycloalkanols (C5, C7, C8, and C12), alkan-2-ols (C3, C5, C6, and C8), 3-hexanol, neopentyl alcohol, a number of benzyl alcohols, dl- and (S)-1-phenylethanol, cyclopentyl- and cyclohexylmethanols, the exo- and endo-borneols, and norborneols.Reactions were carried out with an excess of the alcohol in acetonitrile solution containing 2,6-di-tert-butyl-4-methylpyridine.Products were alkenes, ethers, and N-substituted acetamides, depending on the structure of the alcohol.Thianthrene (Th) and its 5-oxide (ThO) were formed in equal amounts.The sum of amounts of products from the alcohol was equal to the amount of ThO.All reactions are interpretable on the basis of the ultimate formation and further reactions of a 5-alkoxythianthreniumyl ion (ROTh(+)).The predominant formation of nortricyclene from the norborneols is striking and is discussed.Swern-Moffatt-type oxidations of the alcohols were not observed.
- Shine, Henry J.,Yueh, Wang
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p. 3553 - 3559
(2007/10/02)
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- THE THERMAL DEALKYLATION OF 2-CHLORO-4,6-BIS(BORNYL- AND NORBORNYLAMINO)-s-TRIAZINES
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The thermal dealkylation of 2-chloro-4,6-bis(isobornylamino)-s-triazine (I), 2-chloro-4,6-bis(bornylamino)-s-triazine (II), 2-chloro-4,6-bis(exo-norbornylamino)-s-triazine (III) and 2-chloro-4,6-bis(endo-norbornylamino)-s-triazine (IV) was performed at 250 deg C.The high degree of dealkylation in the case of isobornyl derivative I was ascribed to a reaction via a seven-membered cyclic transition state, as well as to steric interaction of the dimethylmethylene group and the triazine ring.The presence of tricyclenes in the dealkylation products of this derivative alsoindicates that the reaction partially takes place with charge separation, i.e. by the anchimeric assistance of the C-6 atom.The lower degree of dealkylation of bornyl derivative II is in agreement with the lower reactivity of the endo-isomer and probably takes place via three different transition states yielding three products.The dealkylation of norbornyl derivatives (exo-III and endo-IV) was successful only in the case of the exo-isomer yielding the expected products, while the endo-isomer under these experimental conditions did not give any dealkylation products.
- Tadic, Zivorad D.,Jovanovic, Bratislav Z.,Antonovic, Dusan G.
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p. 256 - 260
(2007/10/02)
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- NOVEL PRODUCTS FROM BECKMANN FRAGMENTATION OF CAMPHOR OXIME IN POLYPHOSPHORIC ACID
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Heating camphor oxime with PPA affords, besides the known fragmentation products isoaminocamphor (4) and β-campholenonitrile (13), four isomeric ketones C10H14O resulting from intramolecular acylation of the intermediate α-campholenonitrile (3).The ketones have been identified as 5-ketocamphene (6), 6-ketocamphene (8), tricyclenone (9), and endo-2,4-dimethylbicyclooct-2-ene-7-one (14).The latter results from a novel ring expansion, probably by way of a protonated cyclopropane.
- Hill, Richard K.,McKinnie, B. Gary,Conley, Robert T.,Darby, Paul S.,Halbeek, Herman van,Holt, Elizabeth M.
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p. 3405 - 3412
(2007/10/02)
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- Thermolysis and Photolysis of the Azoalkane 4,5-Diaza-7,8,8-trimethyltricyclo3,7>non-4-ene: 1,3-Diradical and Diazoalkane Formation
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On benzophenone-sensitized photolysis at 350 nm the azoalkane 3 denitrogenates exclusively into 2,3,3-trimethyltricyclo2,6>heptane (5), while direct photolysis at 350 nm affords the tricycloheptane 5 as major product and 2,3,3-trimethyl-4-vinylcyclopentene (6) as minor product.With increasing temperature the vinylcyclopentene 6 increases in the direct photolysis.On preparative laser photolysis at 333 nm the diazo-2-(2,3,3-trimethylcyclopenten-4-yl)ethane (8) accumulates, which on subsequent photolysis is shown to produce the vinylcyclopentene 6 via the corresponding carbene intermediate.The diazoalkane 8 does not cyclize back to the azoalkane 3.The thermolysis leads essentially quantitatively to the tricycloheptane 5, with only traces of the vinylcyclopentene 6.These results are rationalized mechanistically in terms of a diazenyl diradical as common intermediate for all three denitrogenation modes.It is proposed that the divergent chemical behavior of the diazenyl diradicals produced in the three forms of activation (triplet-sensitized and direct photolysis and thermolysis) is best understood in terms of distinct spin multiplicities and electronic configurations of the diradical intermediates.In this tritopic process it is shown by means of a Salem diagram that the D?,? diazenyl diradical serves as precursor to the tricycloheptane 5 via the 1,3-diradical 4, while the D?,? diradical is responsible as intermediate for the vinylcyclopentene 6 via the diazoalkane 8.
- Adam, Waldemar,Gillaspey, William D.,Peters, Eva-Maria,Peters, Karl,Rosenthal, Robert J.,Schnering, Hans Georg von
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p. 580 - 586
(2007/10/02)
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- Steroidal N-Nitroamines. Part 3. Pyrolytic Denitroamination of N-Nitroamino-adamantane and -bornane, and of Several Steroidal N-Nitroamines
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The thermal decomposition of several nitroamines has been investigated.The axial nitroamines 6β-nitroamino-5α-cholestan-3β-yl acetate (1) and 23R-nitroamino-(20S,22S,25S)-5β-spirostan-3β-yl acetate (8) gave exclusively nitrogen-free olefins.The trans-diaxial α-hydroxy nitroamines (2) and (3) afforded the 5α- and 4α-oxirane (6) and (7), and small amounts of the corresponding trans-diols (4) and (5).The 7β- and 7α-nitroaminocholest-5-en-3β-yl acetate (10) and (11) gave 7-oxocholesteryl acetate (14) and a mixture of the 7β- and 7α-alcohol (12) and (13) with 50 and 33percent inversion of configuration, respectively.The oxidation product adamantanone (16) was produced together with adamantan-2-ol (20) in the pyrolysis of 2-nitroaminoadamantane (19).Carbon-carbon rearrangement was observed in the case of exo-2-nitroaminobornane (22) and 20β-nitroaminopregn-5-en-3β-yl acetate (25).The nitroamine (25) yielded the 3-O-acetyl derivatives of pregna-5,20-dien-3β-ol, (29), pregna-5,17(20)(E)-dien-3β-ol, (30), 3β-hydroxypregn-5-en-20-one, (28), 17α-methyl-D-homoandrost-5-ene-3β,17aβ-diol, (31), and a mixture of pregn-5-ene-3β,20-diols (26) and (27).Camphene (23) and tricyclene (24) was obtained from exo-2-nitroaminobornane (22).Mechanisms for the formation of these products are discussed.
- Francisco, Cosme G.,Freire, Raimundo,Hernandez, Rosendo,Melian, Daniel,Salazar, Jose A.,Suarez, Ernesto
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p. 2325 - 2328
(2007/10/02)
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- COMPETITIVE DIRADICAL AND DIAZOALKANE FORMATION IN THE THERMOLYSIS AND PHOTOLYSIS OF THE AZOALKANE 7,7,8-TRIMETHYL-2,3-DIAZATRICYCLO4,8>NON-2-ENE
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On laser photolysis of azoalkane 1 at elevated temperature, besides the expected denitrogenation into the tricyclane 3 via 1,3-diradical 2, the diazolkane 7 is directly observed, denitrogenating into vinylcyclopentene 5.
- Adam, Waldemar,Gillaspey, William D.
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p. 1699 - 1702
(2007/10/02)
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- Effect of Sulfate Ions on Activity of TiO2, Fe2O3 and ZrO2 for the 2-Pinene Isomerization Reaction
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Treatment of titanium oxide, Fe2O3 and ZrO2 with (NH4)2SO4 brought high catalytic activity for isomerization of 2-pinene.The selectivities of the catalysts for formation of camphene and 1,7,7-trimethyltricyclo2.6>heptane(tricyclene) were high (60-70 percent).The effect of sulfate ions has been interpreted in terms of surface acid strenght.Key words: Oxides / Sulphate ion / Isomerization / 2-Pinene
- Ohnishi, Ryuichiro,Morikawa, Toshiyuki,Hiraga, Yoshizumi,Tanabe, Kozo
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p. 205 - 210
(2007/10/02)
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- Electronic Effects of Polar Substituents in the Gas Phase Unimolecular Elimination of 4-Substituted Isobornyl Acetates
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The rates of gas-phase elimination of a series of 4-substituted isobornyl acetates have been measured in the presence of propene between 209-370 deg C and within a pressure range 37-153 Torr; a static system with seasoned vessels was used.The reaction are unimolecular, homogeneous, and obey a first-order rate law; electron-withdrawing substituents at C(4) cause a diminution in the elimination rate, such that ρ1 -0.69 in a Hammett treatment.The temperature dependence of the rate coefficients is illustrated for the Arrhenius equation for isobornyl acetate: logk/s-1=(12.82+/-0.13)-(189.2+/-1.5)kJmol-1/2.303RT.The results are consistent with a cyclic transition state in which C(2)-O cleavage is more advanced than that of C(3)-H.The major primary product of elimination of isobornyl acetate is bornylene, which partially isomerises to camphene and tricyclene under the reaction conditions.Bornylene also undergoes a retro-Diels-Alder reaction to yield the trimethylcyclopentadiene and ethylene.
- Chuchani, Gabriel,Hernandez A, Jose A.,Morris, David G.,Shepherd, Alistair G.
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p. 917 - 922
(2007/10/02)
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- Transformations of β-Pinene over Platinum-Alumina Catalyst. Part-I: Influence of Contact Time, Temperature and Platinum Concentration
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The catalytic transformations of β-pinene have been investigated over platinum-alumina dual function catalyst containing varying amounts of platinum in the temperature range 200 to 400 deg C.In addition, the influence of contact time on the rate and distribution of products has been studied over 0.6percent platinum-alumina at 300 deg C.The performance of the catalyst remains unchanged by its pretreatment either in hydrogen or in oxygen prior to catalytic run.The dehydrogenation activity of the catalyst increases upto 350 deg C beyond it declines. β-Pinene isomerizes via two parallel paths: one giving rise to bi- and tricyclic products such as camphene, α-pinene, bornylene and tricyclene and the other giving monocyclic compounds such as dipentene, terpinolene, α- and γ-terpinenes.The terpinenes have been identified as the immediate precursors of cymene.Apart from this, the terpinenes undergo disproportionation to menthenes and menthanes.At higher values of contact time and temperature, menthenes and menthanes get dehydrogenated to cymenes.Increase of platinum concentration inhibits both isomerization and dehydrogenation activities of the catalyst.This decrease is ascribed to reduction of the acid sites and enhancement of platinum crystallite size.Disproportionation reaction is favoured by strong acid sites and small well dispersed platinum crystallites.
- Mathur, P.,Krishnasamy, V.,Chandrasekharan, K.
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p. 970 - 974
(2007/10/02)
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- Amines as Dehalogenating Agents. IV. Hydrocarbons, N-Bornyl- and N-Isobornylaniline Formation in the Reaction between 3-Bromocamphor and N-Methylaniline
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N-Methylanilin (4) reagiert bei 200 deg C im Vergleich zu N,N-Dimethylanilin entweder mit 3-Bromcamphor (2) oder Camphor (3) zu den Kohlenwasserstoffen, Camphen 5 und Tricyclen 6 und N-Bornylanilin (exo-endo-Isomers 7).Bei der Reaktion mit 3 ist Saeurekatalyse notwenig.Untersuchungen zum Mechanismus erlauben es, anzunehmen, dass Camphoranil 8 ein gemeinsames Zwischenprodukt fuer alle Produkte und 4 der H-Donator in den Reduktionsstufen ist, auf der Grundlage von kinetischen und stereochemischen Beweisen und unabhaengigen chemischen Experimenten.
- Giumanini, Angelo G.,Musiani, Marco M.
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p. 423 - 428
(2007/10/02)
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- REACTIONS OF TERPENES IN DIPOLAR APROTIC SOLVENTS. PART III. ISOMERIZATION OF SOME MONOTERPENE HYDROCARBONS
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Acyclic (myrcene, ocimene, alloocimene), monocyclic (limonene) and bicyclic (α-pinene, β-pinene, (+)-3-carene) terpene hydrocarbons heated in dipolar aprotic solvents (DMF, DMSO, TMS) undergo complex conversions where isomerization processes prevail.The isomerization degree of particular hydrocarbons depends both on the structure of initial compound and the type of solvent used.
- Matawowski, Aleksander
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p. 469 - 479
(2007/10/02)
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