- Exploiting the Synthetic Potential of Sesquiterpene Cyclases for Generating Unnatural Terpenoids
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The substrate flexibility of eight purified sesquiterpene cyclases was evaluated using six new heteroatom-modified farnesyl pyrophosphates, and the formation of six new heteroatom-modified macrocyclic and tricyclic sesquiterpenoids is described. GC-O analysis revealed that tricyclic tetrahydrofuran exhibits an ethereal, peppery, and camphor-like olfactoric scent.
- Oberhauser, Clara,Harms, Vanessa,Seidel, Katja,Schr?der, Benjamin,Ekramzadeh, Kimia,Beutel, Sascha,Winkler, Sven,Lauterbach, Lukas,Dickschat, Jeroen S.,Kirschning, Andreas
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p. 11802 - 11806
(2018/09/10)
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- The formal total synthesis of FR252921-An immunosuppressant
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The formal total synthesis of FR252921 is described. The key steps include the preparation of three fragments starting from 1,4-butanediol, (R)-malic acid, and prenol, respectively, followed by two consecutive peptide couplings of the three fragments. Other key steps involve an allene-type rearrangement or enyne isomerization to install the triene moiety, a Seebach methylation, a Julia olefination to construct the trisubstituted diene unit, and an enzymatic resolution strategy to generate the C-18 stereocenter.
- Yadav,Sengupta, Sandip
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p. 376 - 388
(2013/03/13)
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- Total synthesis and biological evaluation of methylgerambullone
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First total synthesis of methylgerambullone (MGB, 1) isolated from Glycosmis angustifolia was completed via a convergent route. The effect of MGB on the contractile responses of the isolated guinea-pig ileum induced by acetylcholine was investigated. As a result, it showed a potent relaxation rate (78.66 ± 4.30% at 100 mg/L) in a concentration-dependent manner on longitudinal smooth muscle contraction of isolated guinea-pig ileum induced by 1 μM acetylcholine.
- Moon, Jong Taik,Ha, Sung Hoon,Lee, So Hyung,Kwon, Tae Hui,Oh, Chun Rim,Kim, Young Deuk,Kim, Jungahn,Choo, Dong Joon,Lee, Jae Yeol
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experimental part
p. 52 - 55
(2010/04/24)
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- IspG converts an epoxide substrate analogue to (E)-4-hydroxy-3-methylbut-2- enyl diphosphate: Implications for IspG catalysis in isoprenoid biosynthesis
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(Chemical Equation Presented) IspG is an intriguing enzyme in bacteria, parasite, and plant isoprenoid biosynthesis, and its catalytic mechanism remains elusive. We report here the synthesis of (2R,3R)-4-hydroxy-3-methyl-2,3- epoxybutanyl diphosphate (Epoxy-HMBPP), a proposed intermediate in one of the frequently cited mechanistic models. We have also demonstrated that this epoxide analogue is a catalytically competent IspG substrate. This study represents the first mechanistic study of this important enzyme.
- Nyland II, Rodney L.,Xiao, Youli,Liu, Pinghua,Freel Meyers, Caren L.
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supporting information; experimental part
p. 17734 - 17735
(2010/04/01)
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- Stereoselective synthesis of chiral tertiary alcohol building blocks via neighbouring group participation from tri-substituted olefins
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A regio- and stereoselective preparation of chiral quaternary 1,2/1,3-diols from acyclic tri-substituted alkenes is disclosed. Optically active tertiary alcohols are the constituents of several bioactive natural products, pharmaceuticals and a general met
- Raghavan, Sadagopan,Sreekanth
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p. 1169 - 1174
(2008/09/18)
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- Intramolecular Formal oxa-[3 + 3] Cycloaddition Approach to the ABD System of Phomactin A
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(Equation Presented) The ABD-ring of phomactin A was synthesized using an intramolecular formal oxa-[3 + 3] cycloaddion of an α,β-unsaturated iminium salt tethered to a 1,3-diketone. This represents the first time that the 12-membered ring has been formed
- Cole, Kevin P.,Hsung, Richard P.
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p. 4843 - 4846
(2007/10/03)
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- Natural and unnatural terpenoid precursors of insect juvenile hormone
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The biosynthesis of insect juvenile hormone (JH) is due, in part, to the precise head-to-tail coupling of allylic and homoallylic diphosphate substrates, as catalyzed by one or more prenyltransferases. To better understand this enzyme's role in JH production, homodimethylallyl diphosphate and both the natural and unnatural homologs of geranyl diphosphate have been prepared as potential substrates for insect prenyltransferase. These latter materials were constructed in a convergent manner by olefination of the corresponding trisnoraldehydes obtained from either terminal oxidative cleavage of geraniol or higher-order cuprate conjugate addition to acrolein. To aid in characterizing the nature of the terpenoid skeletons formed from our in vitro studies, homologous derivatives of farnesol were also prepared by anion coupling of the geranyl derivatives to either C5 or C6 allylic bromides. The preparation of these materials and the results of incubations with larval corpora allata homogenates of the lepidopteran Manduca sexta are described.
- Sen, Stephanie E.,Ewing, Gregory J.
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p. 3529 - 3536
(2007/10/03)
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