- Versatile synthesis of cadalene and iso-cadalene from himachalene mixtures: Evidence and application of unprecedented rearrangements
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From a mixture of α-, β- and γ-himachalenes extracted from waste wood of Atlas cedar (Cedrus atlantica), cadalene (1,6-dimethyl-4-isopropylnaphthalene) and iso-cadalene (1,6-dimethyl-3-isopropylnaphthalene) were produced in two steps with up to 71percent ± 5percent yield through the ar-himachalene intermediate using I2 and/or AlCl3 as reagents. The selectivity is shown to sharply depend on the operating conditions: while I2/AlCl3 in dichloromethane promotes the formation of cadalene, the formation of iso-cadalene is favored in the presence of AlCl3 in cyclohexane. The bicyclic aromatic compounds were thus obtained through unique rearrangements involving sequential C–C bond cleavage/formation and hydride transfer processes. In the absence of AlCl3 or I2, dihydrocurcumene was also found to be formed with up to 70percent selectivity. A tentative mechanism is proposed and discussed.
- Ait El Had, Mustapha,Oukhrib, Abdelouahd,Zaki, Mohamed,Urrutigo?ty, Martine,Benharref, Ahmed,Chauvin, Remi
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supporting information
p. 1851 - 1854
(2020/03/23)
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- Reaction routes in catalytic reforming of poly(3-hydroxybutyrate) into renewable hydrocarbon oil
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Poly(3-hydroxybutyrate) or PHB is an energy storage material of microbial organisms and can be reformed into hydrocarbon oils rich with aromatic compounds. This work investigated the main reaction routes from PHB to the key intermediates and final hydrocarbons. The main sequential reactions under catalysis of phosphoric acid at moderate temperatures (200-230 °C) consist of: (1) decomposition of PHB into crotonic acid, a major monomeric intermediate, (2) deoxygenation of crotonic acid, and (3) combination of the deoxygenated molecules. The oxygen in PHB is removed as CO2 and H2O in stage (2), involving decarboxylation and ketonization of crotonic acid. The main aromatic compounds are formed in stage (3) from propylene and 2,3-dimethyl-2-cyclopenten-1-one as two key intermediates, the former from decarboxylation and the latter from ketonization of crotonic acid. The reaction routes reveal that the formation of aromatics is affected to a great extent by the concentrations of phosphoric acid and water in the reaction, which can be used to control the composition of hydrocarbon oil.
- Kang, Shimin,Yu, Jian
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p. 30005 - 30013
(2015/05/13)
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- Sesquiterpenoid constituents of the liverwort Marsupella aquatica
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Nine new amorphane sesquiterpenoids, (+)-7β-hydroxyamorpha-4,11-diene, (-)-9α-hydroxyamorpha-4,7(11)-diene, (-)-3α-hydroxyamorpha-4,7(11)-diene, (-)-3α-acetoxyamorpha-4,7(11)-diene, (-)-amorpha-4,7(11)-dien-3-one, (+)-2,8-epoxyamorpha-4,7(11)-diene, (+)-5,9-epoxyamorpha-3,7(11)-diene, (-)-2α-hydroxyamorpha-4,7(11)-diene and (-)-2β-acetoxyamorpha-4,7(11)-diene, were isolated from the essential oil of the liverwort Marsupella aquatica, collected near Gaschurn/Montafon, Austria. The isolated compounds and their chemical transformations were investigated using enantioselective GC and extensive spectroscopic studies (HRMS, 1H, 13C and 2D NMR). The absolute configuration of most of the isolated compounds were established by conversions to known compounds. In addition, 1H, and 13C NMR data of (-)-myltayl-4-ene are reported for the first time.
- Adio, Adewale M.,von Reuss, Stephan H.,Paul, Claudia,Muhle, Hermann,Koenig, Wilfried A.
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p. 1245 - 1253
(2008/03/12)
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- Synthetic approaches towards trans-calamenene and related molecular modelling studies
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Synthesis of cadalene (12), γ-calacorene (13), epizonarene (9A)-zonarene (9B) and (+/-)-calamenene (4) from epibicycloquiphellandrene (6), which was prepared from 7(S)-isopropyl-10(R)-methyl-1(S)-4-oxobicyclodec-5-ene (5) in quantitative yields, is reported.Molecular modelling studies of all the compounds are also reported.
- Bhonsle, Jayendra B.
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p. 372 - 379
(2007/10/03)
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- OXIDATION OF AZULENE DERIVATIVES. AUTOXIDATION OF GUAIAZULENE IN A POLAR APROTIC SOLVENT
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Autoxidation of guaiazulene at 100 deg C in N,N-dimethylformamide afforded twenty-three separable products including seven known compounds.Most of these new compounds possess highly interesting structures of azulenoquinone, inden-1-one, benzocyclobutadien
- Nozoe, Tetsuo,Takekuma, Shin-ichi,Doi, Masashi,Matsubara, Yoshiharu,Yamamoto, Hiroshi
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p. 627 - 630
(2007/10/02)
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- NEW SYNTHESES OF A CASSIA KETONE
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Short synthesis of Cassia ketone from 6-methyl-5-hepten-2-one are reported.
- Ho, Tse-Lok,Liu, Shing-Hou
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p. 463 - 466
(2007/10/02)
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