- SYNTHESIS OF NEW HUMULENE DERIVATIVES; (2E,6E,9E)- AND (2Z,6E,9E)-CYCLOUNDECATRIENONES, BY INTRAMOLECULAR ALKYLATION OF PROTECTED CYANOHYDRIN. A ROUTE TO HUMULENE.
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Synthesis of (3E,6E,9E)-2,5,5,9-tetramethyl-2,6,9-cycloundecatrienone (4) and (2Z,6E,9E)-2,5,5,9-tetramethyl-2,6,9-cycloundecatrienone (16) based on the intramolecular alkylation of protected cyanohydrin and conversion of the (E,E,E)-trienone 4 to humulene (3) are presented.
- Takahashi, Takashi,Kitamura, Kyoko,Tsuji, Jiro
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- An Unusual Skeletal Rearrangement in the Biosynthesis of the Sesquiterpene Trichobrasilenol from Trichoderma
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The skeletons of some classes of terpenoids are unusual in that they contain a larger number of Me groups (or their biosynthetic equivalents such as olefinic methylene groups, hydroxymethyl groups, aldehydes, or carboxylic acids and their derivatives) than provided by their oligoprenyl diphosphate precursor. This is sometimes the result of an oxidative ring-opening reaction at a terpene-cyclase-derived molecule containing the regular number of Me group equivalents, as observed for picrotoxan sesquiterpenes. In this study a sesquiterpene cyclase from Trichoderma spp. is described that can convert farnesyl diphosphate (FPP) directly via a remarkable skeletal rearrangement into trichobrasilenol, a new brasilane sesquiterpene with one additional Me group equivalent compared to FPP. A mechanistic hypothesis for the formation of the brasilane skeleton is supported by extensive isotopic labelling studies.
- Murai, Keiichi,Lauterbach, Lukas,Teramoto, Kazuya,Quan, Zhiyang,Barra, Lena,Yamamoto, Tsuyoshi,Nonaka, Kenichi,Shiomi, Kazuro,Nishiyama, Makoto,Kuzuyama, Tomohisa,Dickschat, Jeroen S.
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- Synthesis of novel acetates of β -caryophyllene under solvent-free lewis acid catalysis
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Acylation of β-caryophyllene, a sesquiterpene hydrocarbon with acetic anhydride, was carried out under mild catalytic conditions using Lewis acids such as BF3 Et2O, ZnCl2, FeCl3, I2 and AlCl3/su
- Jaitak, Vikas,Kaul,Singh, Bikram
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- STEREOSPECIFIC SYNTHESIS OF HUMULENE BY TITANIUM-INDUCED DICARBONYL COUPLING
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An efficient stereospecific synthesis of humulene was accomplished using titanium-induced cyclization of 3,3,7-trimethyl-11-oxoundeca-4E,7E-dienal as the key step.
- McMurry, John E.,Matz, James R.
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- A stable rearrangement product of humulene-4,5-epoxide
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Humulene-4,5-monoepoxide, 1, may rearrange to the cyclopropyl diol 2 during chromatography over silica. The rearrangement can be reversed with acid.
- Carman, Raymond M.
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p. 1441 - 1442
(2008/09/20)
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- Monoepoxidation of humulene 2,3-epoxide to humulene 2,3;6,7-diepoxides. Observation of the rotation of the double bond plane by 1H NMR spectral analysis and conformation
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The reaction of (6E,9E)-humulene 2,3-epoxide (7) with m-CPBA produced two known humulene 2,3;6,7-diepoxides (8 and 9), and careful analysis of the 1H NMR of 7 at various temperatures suggested an equilibrium of four possible conformations, CT,
- Hayano, Kiyoharu,Mochizuki, Katsura
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p. 387 - 393
(2007/10/03)
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- Short syntheses of (±)-δ-araneosene and humulene utilizing a combination of four-component assembly and palladium-mediated cyclization
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(Matrix presented) The four components shown are assembled in two steps, and the product is converted to araneosene by a short sequence.
- Hu, Tao,Corey
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p. 2441 - 2443
(2007/10/03)
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- (+)-(10R)-Germacrene A synthase from goldenrod, Solidago canadensis; cDNA isolation, bacterial expression and functional analysis.
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Profiling of sesquiterpene hydrocarbons in extracts of goldenrod, Solidago canadensis, by GC-MS revealed the presence of both enantiomers of germacrene D and lesser amounts of germacrene A, alpha-humulene, and beta-caryophyllene. A similarity-based cloning strategy using degenerate oligonucleotide primers, based on conserved amino acid sequences in known plant sesquiterpene synthases and RT-PCR, resulted in the isolation of a full length sesquiterpene synthase cDNA. Functional expression of the cDNA in E. coli, as an N-terminal thioredoxin fusion protein using the pET32b vector yielded an enzyme that was readily purified by nickel-chelate affinity chromatography. Chiral GC-MS analysis of products from of (3)H- and (2)H-labelled farnesyl diphosphate identified the enzyme as (+)-(10R)-germacrene A synthase. Sequence analysis and molecular modelling was used to compare this enzyme with the mechanistically related epi-aristolochene synthase from tobacco.
- Prosser, Ian,Phillips, Andy L,Gittings, Simon,Lewis, Mervyn J,Hooper, Antony M,Pickett, John A,Beale, Michael H
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p. 691 - 702
(2007/10/03)
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- A BIOMIMETIC CHEMICAL SYNTHESIS OF HUMULENE FROM FARNESOL
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The first synthesis of humulene (1) by a biomimetic cation-olefin cyclization route is reported.
- Corey, E. J.,Daigneault, Sylvain,Dixon, Brian R.
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p. 3675 - 3678
(2007/10/02)
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- Synthesis of Macrocyclic Terpenoids by Intramolecular Carbonyl Coupling: Flexibilene and Humulene
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Total syntheses of two macrocyclic sesquiterpene hydrocarbons, humulene (1) and flexibilene (2) are discussed in detail.Both were prepared in high overall yield by titanium-induced cyclization of the appropriate keto aldehyde precursors (4 and 9, respectively), themselves obtained by coupling of the vinylic zirconium reagent 22 with pi-allylpalladiums 26 and 23.
- McMurry, John E.,Matz, James R.,Kees, Kenneth L.
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p. 5489 - 5498
(2007/10/02)
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- NEW STEREO- AND REGIOSPECIFIC SYNTHESIS OF HUMULENE BY MEANS OF THE PALLADIUM CATALYZED CYCLIZATION OF HALOALKENYLBORANES
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We describe a new stereo- and regiospecific synthesis of humulene, the major sesquiterpene of hops, by means of the palladium-catalyzed cyclization of haloalkenylboranes derived from geranyl halides via 4 principal steps.
- Miyaura, Norio,Suginome, Hiroshi
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p. 761 - 764
(2007/10/02)
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- Chemistry of Hop Constituents. Part 42. The Formation and Characterisation os Sesquiterpene Episulphides in the Essential Oil of Hops
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The novel episulphides, humulene-1,2- and -4,5-episulphide and caryophyllene-4,5-episulphide, identified as components of hop oil, particularly that from hops treated with sulphur during the growing season, have been prepared under very mild conditions by the u.v.-promoted addition of sulphur to the sesquiterpenes, and have been characterised largely by i.r. and 1H n.m.r. spectroscopy.
- Peppard, Terence L.,Sharpe, F. Richard,Elvidge, John A.
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p. 311 - 313
(2007/10/02)
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