- Synthesis from geraniol of (2E,6E,10E,14E)-16-hydroxygeranylgeraniol and some of its derivatives
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Several α,ω-bifunctional derivatives of E,E,E-geranylgeraniol were prepared via convergent synthesis starting with geraniol (8), which was converted in three steps into the tetrahydropyranyl ether of 8-chlorogeraniol (9) and 8-hydroxygeranylphenylsulfone (10). Combination of synthons 9 and 10 with subsequent reductive removal of the phenylsulfonyl group produced the tetrahydropyranyl ether of ω-hydroxygeranylgeraniol (5), hydrolysis of which gave exclusively trans-ω-hydroxygeranylgeraniol (1). Derivatives 5-7 of geranylgeraniol were synthesized using standard methods.
- Grin'ko,Kulcitki,Ungur,Barba,Delyanu,Vlad
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Read Online
- Palladium-catalyzed substitution of allylic alcohols with sulfinate salts: A synthesis of bicalutamide
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A method is presented for the direct substitution of allylic alcohols with sodium arylsulfinates. The process involves a cooperative action of palladium catalysts, phenylboronic acid and titanium tetraisopropoxide. By taking advantage of this protocol, we achieved a concise synthesis of bicalutamide, an anti-androgen compound for treating prostate cancer.
- Jhang, Yin-Jia,Chang, Chieh-Yu,Lin, Yu-Huan,Lee, Chein-Chung,Wu, Yen-Ku
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supporting information
(2021/05/04)
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- Rh2(II)-Catalyzed intermolecular N-Aryl aziridination of olefins using nonactivated N atom precursors
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The development of the first intermolecular Rh2(II)-catalyzed aziridination of olefins using anilines as nonactivated N atom precursors and an iodine(III) reagent as the stoichiometric oxidant is reported. This reaction requires the transfer of an N-aryl nitrene fragment from the iminoiodinane intermediate to a Rh2(II) carboxylate catalyst; in the absence of a catalyst only diaryldiazene formation was observed. This N-aryl aziridination is general and can be successfully realized by using as little as 1 equiv of the olefin. Di-, tri-, and tetrasubstituted cyclic or acylic olefins can be employed as substrates, and a range of aniline and heteroarylamine N atom precursors are tolerated. The Rh2(II)-catalyzed N atom transfer to the olefin is stereospecific as well as chemo- and diastereoselective to produce the N-aryl aziridine as the only amination product. Because the chemistry of nonactivated N-aryl aziridines is underexplored, the reactivity of N-aryl aziridines was explored toward a range of nucleophiles to stereoselectively access privileged 1,2-stereodiads unavailable from epoxides, and removal of the N-2,4-dinitrophenyl group was demonstrated to show that functionalized primary amines can be constructed.
- Deng, Tianning,Mazumdar, Wrickban,Yoshinaga, Yuki,Patel, Pooja B.,Malo, Dana,Malo, Tala,Wink, Donald J.,Driver, Tom G.
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supporting information
p. 19149 - 19159
(2021/11/23)
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- CHINONE-, HYDROCHINOME- AND NAPHTHOCHINONE-ANALOGUES OF VATIQUIONE FOR TREATMENT OF MITOCHONDRIAL DISORDER DISEASES
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The disclosure provides therapeutic compositions (i.e., therapeutic agents) and methods of preventing or treating Friedreich's ataxia in a mammalian subject, reducing risk factors, signs and/or symptoms associated with Friedreich's ataxia (e.g. Complex I deficiency), and/or reducing the likelihood or severity of Friedreich's ataxia. The disclosure further provides novel intermediates for the production of said therapeutic compositions and related reduced versions of said therapeutic compositions, which reduce forms may also be used as therapeutic agents (or prodrugs of the therapeutic agent(s)).
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Page/Page column 212-213
(2021/04/10)
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- Methyl-Shifted Farnesyldiphosphate Derivatives Are Substrates for Sesquiterpene Cyclases
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New sesquiterpene backbones are accessible after biotransformation of presilphiperfolan-8β-ol synthase (BcBOT2), a fungal sesquiterpene synthase, with non-natural farnesyldiphosphates in which methyl groups are shifted by one position toward the diphosphate terminus. One of the macrocycles formed, a new germacrene A derivative, undergoes a Cope rearrangement to iso-β-elemene. Three of the new terpenoids show olfactoric properties that range from an intense peppery note to a citrus, ozone-like, and fruity scent.
- Harms, Vanessa,Schr?der, Benjamin,Oberhauser, Clara,Tran, Cong Duc,Winkler, Sven,Dr?ger, Gerald,Kirschning, Andreas
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supporting information
p. 4360 - 4365
(2020/06/08)
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- PROCESS OF VITAMIN K2 DERIVATIVES PREPARATION
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Provided is an improved process of vitamin K2 derivatives preparation, represented by formula (I) wherein n is an integer from 3 to 13.
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Page/Page column 24; 25
(2019/10/29)
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- Squalene-Hopene Cyclase: On the Polycyclization Reactions of Squalene Analogues Bearing Ethyl Groups at Positions C-6, C-10, C-15, and C-19
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Squalene-hopene cyclase (SHC) has been found to convert acyclic squalene into 6,6,6,6,5-fused pentacyclic triterpenes hopene and hopanol. The enzymatic reactions of squalene analogues bearing ethyl groups in lieu of methyl groups at positions C-6, C-10, C-15, and C-19 have been examined to investigate whether the larger ethyl substituents (a C1 unit increment) are accepted as substrates and to investigate how these substitutions affect polycyclization cascades. Analogue 6-ethylsqualene 19a did not cyclize, which indicates that substitution with the bulky group at C-6 completely inhibited the polycyclization reaction. In contrast, 19-ethylsqualene 19b afforded a wide spectrum of cyclization products, including mono-, bi-, tetra-, and pentacyclic products in a ratio of 6:6:1:2. The production of tetra- and pentacyclic scaffolds suggests that the reaction cavity for D-ring formation site is somewhat loosely packed and can accept the 19-ethyl group, and that a robust hydrophobic interaction exists between the 19-ethyl group and the binding site. In contrast to 19b, 10-ethylsqualene 20a and 15-ethylsqualene 20b afforded mainly mono- and bicyclic products, that is, the polycyclization cascade terminated prematurely at the bicyclic reaction stage. Therefore, the catalytic domains for the 10- and 15-methyl binding sites are tightly packed and cannot fully accommodate the Et substituents. The cyclization pathways followed by the ethyl-substituted substrates in the presence of SHC and lanosterol and β-amyrin synthases are compared.
- Takahashi, Kazunari,Sasaki, Yusuke,Hoshino, Tsutomu
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supporting information
p. 1477 - 1490
(2018/04/06)
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- Reactivity of 2-Nitropyrrole Systems: Development of Improved Synthetic Approaches to Nitropyrrole Natural Products
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Fundamental study of the reactivity of 2-nitropyrrole systems has enabled the identification of effective methods for incorporation of this unusual motif into advanced natural product frameworks. The presence of electron-rich pyrrole N-protecting groups (BOM, Boz) was demonstrated to enable a variety of previously unsuccessful palladium-mediated cross-couplings to be carried out in high yield. Based on this foundation, a series of regio- and stereoselective synthetic routes toward the nitropyrrolin and heronapyrrole families of natural products was developed by our group (G1-3). A full account of the strategic evolution of these approaches is reported here, highlighting the details of the setbacks encountered and eventual successes achieved en route, including the total synthesis of heronapyrrole B. The fundamental studies and completed total syntheses provide general access to the bioactive 2-nitropyrrole natural product manifold and also establish practical and efficient methods for preparation and elaboration of the medicinally relevant 2-nitropyrrole motif.
- Ding, Xiao-Bo,Brimble, Margaret A.,Furkert, Daniel P.
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p. 12460 - 12470
(2018/10/20)
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- Development of a new air-stable structure-simplified nafuredin-γ analog as a potent and selective nematode complex I inhibitor
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Nafuredin-γ, obtained from natural nafuredin, has demonstrated a potent and selective inhibitory activity against nematode complex I. However, nafuredin-γ is unstable in air since its conjugated dienes are oxygen-labile. The instability in air was natural
- Ohtawa, Masaki,Arima, Shiho,Shimizu, Risa,Hanatani, Naomi,Shimizu, Eri,Shiomi, Kazuro,Kita, Kiyoshi,ōmura, Satoshi,Nagamitsu, Tohru
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p. 647 - 654
(2017/05/29)
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- β-Amyrin Biosynthesis: Effect of Steric Bulk at the 6-, 10- and 15-Positions in the 2,3-Oxidosqualene Backbone on Polycyclisation Cascades
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β-Amyrin synthase incubation experiments have been conducted to determine the influence of steric effects at the 6-, 10- and 15-positions of 2,3-oxidosqualene on the polycyclisation pathway. Nor- and ethyl-substituted oxidosqualene analogues were synthesised. Cyclisation of the ethyl-substituted analogues did not occur, but the nor analogues underwent a polycyclisation cascade to yield fully cyclised products with 6/6/6/6/6-fused pentacyclic scaffolds generated via a final oleanyl cation. Previously, we reported that 19- and 23-ethyl-substituted analogues underwent polycyclisation reactions. Therefore, the catalytic domain involved in earlier cyclisation steps is notably compact. In contrast, the catalytic domain in the later cyclisation steps is more loosely packed (less compact) to accommodate the bulky ethyl group. The reaction cavities for recognising branched methyl groups are discussed by comparing β-amyrin synthase with other triterpene cyclases such as lanosterol and hopene synthases.
- Terasawa, Yuri,Sasaki, Yusuke,Yamaguchi, Yuki,Takahashi, Kazunari,Hoshino, Tsutomu
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supporting information
p. 287 - 295
(2017/01/24)
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- N-GLYCOSYLATION OF PEPTIDES AND PROTEINS
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A process for the production of a glycoconjugate by N-glycosylation of a protein or peptide comprising the sequence D/E-X-N-X-S/T, wherein each X is the same or different and is any natural amino acid other than proline, wherein the process comprises reacting the protein or peptide with a polyisoprenyl pyrophosphate of formula (I), or a salt thereof, in the presence of PglB: (I) to produce the glycoconjugate comprising the protein or peptide having a saccharide [SI] linked to the asparagine in the sequence D/E-X-N-X-S/T. Polyisoprenylpyrophosphates used as substrates in the biocatalytic process are also provided, as well as certain glycoconjugates.
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Page/Page column 17; 18
(2015/05/05)
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- Gold nanoparticles decorated with mannose-6-phosphate analogues
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Herein, the preparation of neoglycoconjugates bearing mannose-6-phosphate analogues is described by: (a) synthesis of a cyclic sulfate precursor to access the carbohydrate head-group by nucleophilic displacement with an appropriate nucleophile; (b) introduction of spacers on the mannose-6-phosphate analogues via Huisgen's cycloaddition, the Julia reaction, or the thiol-ene reaction under ultrasound activation. With the resulting compounds in hand, gold nanoparticles could be functionalized with various carbohydrate derivatives (glycoconjugates) and then tested for angiogenic activity. It was observed that the length and flexibility of the spacer separating the sugar analogue from the nanoparticle have little influence on the biological response. One particular nanoparticle system substantially inhibits blood vessel growth in contrast to activation by the corresponding monomeric glycoconjugate, thereby demonstrating the importance of multivalency in angiogenic activity.
- Combemale, Stephanie,Assam-Evoung, Jean-Norbert,Houaidji, Sabrina,Bibi, Rashda,Barragan-Montero, Veronique
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p. 1120 - 1149
(2014/02/14)
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- Rationally designed short polyisoprenol-linked PglB substrates for engineered polypeptide and protein N-glycosylation
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The lipid carrier specificity of the protein N-glycosylation enzyme C. jejuni PglB was tested using a logical, synthetic array of natural and unnatural C10, C20, C30, and C40 polyisoprenol sugar pyrophosphates, including those bearing repeating cis-prenyl units. Unusual, short, synthetically accessible C20 prenols (nerylnerol 1d and geranylnerol 1e) were shown to be effective lipid carriers for PglB sugar substrates. Kinetic analyses for PglB revealed clear KM-only modulation with lipid chain length, thereby implicating successful in vitro application at appropriate concentrations. This was confirmed by optimized, efficient in vitro synthesis allowing >90% of Asn-linked β-N-GlcNAc-ylated peptide and proteins. This reveals a simple, flexible biocatalytic method for glycoconjugate synthesis using PglB N-glycosylation machinery and varied chemically synthesized glycosylation donor precursors.
- Liu, Feng,Vijayakrishnan, Balakumar,Faridmoayer, Amirreza,Taylor, Thomas A.,Parsons, Thomas B.,Bernardes, Goncalo J.L.,Kowarik, Michael,Davis, Benjamin G.
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supporting information
p. 566 - 569
(2014/02/14)
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- Lanosterol biosynthesis: The critical role of the methyl-29 group of 2,3-oxidosqualene for the correct folding of this substrate and for the construction of the five-membered D ring
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Lanosterol synthase catalyzes the polycyclization reaction of (3S)-2,3-oxidosqualene (1) into tetracyclic lanosterol 2 by folding 1 in a chair-boat-chair-chair conformation. 27-Nor- and 29-noroxidosqaulenes (7 and 8, respectively) were incubated with this enzyme to investigate the role of the methyl groups on 1 for the polycyclization cascade. Compound 7 afforded two enzymatic products, namely, 30-norlanosterol (12) and 26-normalabaricatriene (13; 12/13 9:1), which were produced through the normal chair-boat-chair-chair conformation and an atypical chair-chair-boat conformation, respectively. Compound 8 gave two products 14 and 15 (14/15 4:5), which were generated by the normal and the unusual polycyclization pathways through a chair-chair-boat-chair conformation, respectively. It is remarkable that the twist-boat structure for the B-ring formation was changed to an energetically favored chair structure for the generation of 15. Surprisingly, 14 and 15 consisted of a novel 6,6,6,6-fused tetracyclic ring system, thus differing from the 6,6,6,5-fused lanosterol skeleton. Together with previous results, we conclude that the methyl-29 group is critical to the correct folding of 1, with lesser contributions from the other branched methyl groups, such as methyl-26, -27, and -28. Furthermore, we demonstrate that the methyl-29 group has a crucial role in the formation of the five-membered D ring of the lanosterol scaffold. Ringing in the changes: The incubation of 1 with porcine-liver cyclase afforded new nortriterpenes 2 and 3 with 6,6,6,6-fused tetracyclic skeletons, which were produced by chair-boat-chair-chair and chair-chair-boat-chair conformations, respectively (see scheme), thus indicating that the 29-methyl group is critical to the correct folding of oxidosqualene and to the formation of the five-membered D ring for lanosterol biosynthesis. Copyright
- Hoshino, Tsutomu,Chiba, Akifumi,Abe, Naomi
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supporting information
p. 13108 - 13116
(2013/01/15)
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- Gold-catalyzed cyclization of oxo-1,5-enynes
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Cationic gold(I) complexes catalyze the cycloisomerization of oxo-1,5-enynes to form oxatricyclic derivatives through an intramolecular Prins reaction. Georg Thieme Verlag Stuttgart. New York.
- Huguet, Núria,Echavarren, Antonio M.
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supporting information; experimental part
p. 49 - 53
(2012/02/14)
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- Selective C - S bond formation via Fe-catalyzed allylic substitution
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In contrast to the formation of C - O and C - N bonds it was only recently that the selective C - S bond formation by means of transition metal complexes moved more into the center of research. This is somewhat surprising given the fact that the sulfur at
- Jegelka, Markus,Plietker, Bernd
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supporting information; experimental part
p. 3462 - 3465
(2009/12/05)
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- Expeditious and practical synthesis of lycopene
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Our lycopene synthesis highlights the expeditious assembly of the carbon skeleton by the use of a readily available ten-carbon unit, geraniol, rather than the original natural five-carbon building block, isopentenyl pyrophosphate. Furthermore, four oxidation steps by the enzyme desaturases to produce the conjugated carbon-carbon double bonds of lycopene are merged into one-pot double elimination reactions in our synthesis. These accomplished the highly efficient synthesis of all-(E)-lycopene from geraniol through a seven-step sequence in 51% overall yield.
- Choi, Eunho,Jung, Eun Yeo,Koo, Sangho
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supporting information; experimental part
p. 365 - 369
(2009/04/08)
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- π-Allylic sulfonylation in water with amphiphilic resin-supported palladium-phosphine complexes
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π-Allylic substitution of allyl esters with sodium arylsul-finate was performed with an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported phosphine-palladium complex in water as a single reaction medium under heterogeneous conditions to give allyl sulfones in good to high yields. Catalytic asymmetric allylic substitution of cycloalkenyl esters also took place in water using a PS-PEG resin-supported chiral imidazo-indolephosphine- palladium complex to give cycloalkenyl sulfones with up to 81% ee.
- Uozumi, Yasuhiro,Suzuka, Toshimasa
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experimental part
p. 1960 - 1964
(2009/04/04)
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- Squalene-hopene cyclase: Insight into the role of the methyl group on the squalene backbone upon the polycyclization cascade. Enzymatic cyclization products of squalene analogs lacking a 26-methyl group and possessing a methyl group at C(7) or C(11)
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To provide deep insight into the polycyclization reaction of squalene, some analogs were synthesized and incubated with the cell-free homogenates of the recombinant Escherichia coli encoding the wild-type squalene cyclase. The presence of C(6)-Me leads to an efficient polycyclization cascade. Substitution of the C(14)-H and the C(18)-H with a methyl group halted the polycylization reaction at the tricyclic ring stage having a 6/6/6-fused ring system and the tetracycle with a 6/6/6/6-fused ring, respectively, both of which were produced according to a Markovnikov closure. Replacement of the C(7)-H and the C(11)-H with a methyl group led to no cyclization. These results, in conjunction with our previous reports, indicated that the methyl positions are important for bringing to completion of the normal polycylization reaction and further demonstrated that the precise steric bulk size at the methyl positions of squalene is critical to the correct folding and the strong binding of the substrate to the squalene cyclase.
- Nakano, Shin-Ichi,Ohashi, Shumi,Hoshino, Tsutomu
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p. 2012 - 2022
(2007/10/03)
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- Synthesis and antimicrobial evaluation of farnesyl diphosphate mimetics
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The synthesis and first antimicrobial evaluation of farnesyl diphosphate mimetics are described. Several analogues (10, 12, 13, and 20) are inhibitors of Candida albicans, Shizosaccharomyces pombe, and Saccharomyces cerevisiae. The activities of analogues 10, 12, and 13, which contain a ω-phenyl moiety and a diphosphate isostere, are not attributable to inhibition of sterol biosynthesis via squalene synthase. Two geranyl phenylsulphones (14 and 15) are potent inhibitors of Escherichia coli. Analogue 15 exhibits potent activity towards Salmonella typhimurium and Pseudomonas aeruginosa (MIC - 2μg/mL) and represents the first type of semi-synthetic terpenoid allylic sulphone active against these bacteria.
- Fairlamb, Ian J.S.,Dickinson, Julia M.,O'Connor, Rachael,Cohen, Louis H.,Van Thiel, Christa F.
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- One-pot synthesis of aryl sulfones from alcohols
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A one-pot synthesis of aryl sulfones from primary alcohols is described. Alcohols were treated with N-bromosuccinimide and triphenylphosphine, followed by addition of sodium arenesulfinate with a catalytic amount of tetrabutylammonium iodide to afford the aryl sulfones in good to high yields.
- Murakami, Teiichi,Furusawa, Kiyotaka
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p. 479 - 482
(2007/10/03)
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- Selective oxidation of allylic sulfides by hydrogen peroxide with the trirutile-type solid oxide catalyst LiNbMoO6
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Chemoselective sulfur oxidation of allylic sulfides containing double bonds of high electron density due to multiple alkyl substituents or extended conjugation was developed using the composite metal oxide catalyst, LiNbMoO6, without any epoxidation of the electron-rich double bond(s). Selective oxidation to either the corresponding sulfoxides or the sulfones was realized by controlling the stoichiometry of the quantitative oxidant, H202. This new oxidant system had general applicability for chemoselective oxidation of various allylic, benzylic, or propargylic sulfides containing unsaturated carbon-carbon bonds with different electron properties. Various functional groups including hydroxy, formyl, and ethers of THP or TBDMS are compatible under this mild oxidation reaction condition.
- Choi, Soojin,Yang, Jae-Deuk,Ji, Minkoo,Choi, Hojin,Kee, Minyong,Ahn, Kwang-Hyun,Byeon, Song-Ho,Baik, Woonphil,Koo, Sangho
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p. 8192 - 8198
(2007/10/03)
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- Oxidation of sulfides to sulfoxides and sulfones with 30% hydrogen peroxide under organic solvent- and halogen-free conditions
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Aromatic and aliphatic sulfides are oxidized to sulfoxides or sulfones in high yield with 30% hydrogen peroxide under organic solvent- and halogen-free conditions. Dialkyl and alkyl aryl sulfides are cleanly oxidized to sulfoxides using aqueous hydrogen peroxide without catalysts. The best catalyst for the sulfone synthesis consists of sodium tungstate, phenylphosphonic acid, and methyltrioctylammonium hydrogensulfate. Co-existing primary or secondary alcohol or olefinic moieties are unaffected under such conditions.
- Sato, Kazuhiko,Hyodo, Mamoru,Aoki, Masao,Zheng, Xiao-Qi,Noyori, Ryoji
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p. 2469 - 2476
(2007/10/03)
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- Cyclohexenonic long-chain fatty alcohols as neuronal growth stimulators
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Neurotrophic factors play an important role in the development and maintenance of neurons, thus providing a suitable therapeutic approach for the treatment of neurodegenerative diseases. However, their clinical use has revealed problematic because of a number of technical and biological disadvantages. Among the different strategies proposed to overcome such difficulties, the search for non-peptide substances with neurotrophic potential is giving promising results. Here we will expose major findings in this field, drawing special attention to cyclohexenonic long-chain fatty alcohols, a novel family of compounds that promote neuronal survival and neurite outgrowth.
- Luu, Bang,Gonzalez De Aguilar, Jose-Luis,Girlanda-Junges, Celine
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p. 1439 - 1460
(2007/10/03)
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- 3-(15-hydroxypentadecyl)-2,4,4-trimethyl-2-cyclohexen-1-one and its effect on neuropeptide secretion
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The aim of the present study was to describe the synthesis of a trimethyl cyclohexenonic long chain fatty alcohol (t-CFA), and analyze its biological activity. Specifically, 3-(15-hydroxypentadecyl)-2,4,4-trimethyl-2-cyclohexen-1-one, the t-CFA containing
- Girlanda-Junges, Celine,Lutz-Bucher, Bernadette,Gonzalez de Aguilar, Jose-Luis,Loeffler, Jean-Philippe,Luu, Bang
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p. 2537 - 2539
(2007/10/03)
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- The first total synthesis of (-)-sinulariol-B and three other cembranoids
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The first total synthesis of (-)-sinulariol-B, a marine cembrandiol, was achieved from geraniol. Three other cembranoids were also synthesized from (- )-sinulariol-B.
- Lan, Jiong,Li, Jing,Liu, Zuosheng,Li, Yulin,Chan, Albert S. C.
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p. 1877 - 1885
(2007/10/03)
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- First total synthesis of (±)-13-hydroxyneocembrene
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First total synthesis of (±)-13-hydroxyneocembrene (1), starting from 6-methyl-5-hepten-2-one (6) and geraniol (7), is described. The key steps are (i) the addition of sulfur-stabilized carbanion 12 to aldehyde 9, (ii) the synthesis of 18 by using phase-transfer catalyzed coupling reaction, and (iii) low-valent titanium-induced intramolecular coupling of oxo aldehyde 3 to afford the target molecule after the final deprotection.
- Xing, Yacheng
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p. 595 - 600
(2007/10/03)
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- An Efficient Total Synthesis of (+/-)-Sinulariol-B
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The first total synthesis of (+/-)-Sinulariol-B, a marine cembrandiol, was achieved in ten steps and ca. 10 percent overall yield from E-geraniol (8). The key steps were the coupling of sulfone 7 with allylic chloride 6 and the macrocyclization of precursor 5 by sulfone- and thioether-stabilized carbanionic alkylations, respectively.
- Yue, Xiangjun,Lan, Jiong,Li, Jing,Liu, Zuosheng,Lin, Yulin
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p. 133 - 140
(2007/10/03)
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- Superacidic low temperature cyclization of terpenylphenyisulfones
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The superacidic cyclization of aliphatic and partially cyclized C10- C20 terpenylphenylsulfones proceeds structure-selectively and stereospecifically, affording α- or mixtures of α- and γ-isomers of completely cyclized terpenylphenylsulfones. The configuration of the phenylsuffonylmethylene group in the cyclized products is predetermined by the configuration of the allylic double bond in the starting compounds.
- Kulcitki, Veaceslav,Ungur, Nicon,Vlad, Pavel F.
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p. 11925 - 11934
(2007/10/03)
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- Total synthesis of polyprenylhydroquinols and benzoquinones
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The total synthesis of polyprenylhydroquinols and benzoquinones is described.First, two appropriate aromatic allyl carbonates (moieties with one and two prenyls) and two activated bifunctional terpenyl derivatives (moieties with two and three prenyls) were synthesized.These molecules were then reacted together using a highly regio- and stereoselective coupling with Pd(PPh3)4 as a catalyst.The synthesis was achieved by functional group elimination and formation of quinonic and hydroquinonic moieties. - Keywords: polyprenylbenzoquinol; polyprenylhydroquinone; allylcarbonate; ?-allyl palladium complex
- Bouzbouz, Samir,Kirschleger, Bernard,Villieras, Jean
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- Studies on macrocyclic diterpenoids (XIX) - Total synthesis of (RR/SS)-sinulariol-B
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The first total synthesis of (RR/SS)-sinulariol-B (1) was achieved in ten steps and ~ 10% overall yield from E-geraniol (8). The key step was the macrocyclization of precursor 5 by thioether-stabilized carbanionic alkylations.
- Yue,Li
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p. 671 - 674
(2007/10/02)
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- Synthesis of Vinyl Sulfide Analogs of 2,3-Oxidosqualene and Their Inhibition of 2,3-Oxidosqualene Lanosterol-Cyclases
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Syntheses of all trans(6E)-5-, (10E)-9-, (14E)-16- and (18E)-20-thia-2,3-oxidosqualenes as inhibitors of 2,3-oxidosqualene-lanosterol cyclase (OSC) are reported.To mimic the natural geometry of 2,3-oxidosqualene (2,3-OS), we required E-vinyl sulfides which were prepared by condensation of sulfur-substituted Wittig-Horner reagents (α-thioterpenoidyl diphenylphosphine oxides) with appropriate aldehydes.Mixtures of syn and anti α-hydroxydiphenylphosphine adducts were seperated by chromatography and the syn isomers were transformed to the E-vinyl sulfides.Both (6E)-5- and (18E)-20-thia-2,3-OS inhibited OSC from Candida albicans (IC50 = 47 and 0.2 μM, respectively) and rat liver (IC50 = 7.7 and 0.32 μM, respectively).Their activities were compared with those of previously synthesized (6E)-8- and (14E)-13-thia-2,3-Oss (IC50 = 0.68 and 45 μM, C. albicans, IC50 = 34 and 61 μM, rat liver, respectively).The best inhibitor among these compounds for the OSC of C. albicans and rat liver is the (18E)-20-thia-2,3-OS.This result suggests that modification of C-20 region of the 2,3-OS skeleton is an attractive strategy for development of OSC inhibitors.
- Zheng, Yi Feng,Dodd, Dharmpal S.,Oehlschlager, Allan C.,Hartman, Peter G.
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p. 5255 - 5276
(2007/10/02)
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- Surface-mediated reactions. 5. Oxidation of sulfides, sulfoxides, and alkenes with tert-butyl hydroperoxide
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Silica gel mediates the reactivity of (CH3)3COOH, affording a convenient, environmentally benign method for oxidizing sulfides, sulfoxides, and alkenes. Electrophilic oxidation of sulfides and alkenes (Scheme 1A) and nucleophilic oxidation of sulfoxides (Scheme 1B) are apparently involved. Basic alumina mediates the oxidation of sulfoxides.
- Breton, Gary W.
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p. 3825 - 3828
(2007/10/02)
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- Regioselective Preparation of Allylic Sulfones by Palladium-Catalyzed Reactions of Allylic Nitro Compounds with Sodium Benzenesulfinate
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Treatment of allylic nitro compounds with sodium benzenesulfinate in the presence of 5 molpercent of Pd(PPh3)4 in N,N-dimethylformamide (DMF) at 20-70 deg C for 1-10 h resulted in the formation of allylic sulfones with predominance of kinetically controll
- Ono, Noboru,Hamamoto, Isami,Kawai, Takashi,Kaji, Aritsune,Tamura, Rui,Kakihana, Masato
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p. 405 - 410
(2007/10/02)
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- A New Synthesis of Olefins via the Elimination Reaction of β-Tributylstannyl Organosulfur Compounds
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Organosulfur compounds on treatment with butyllithium in tetrahydrofuran followed by tributylstannylmethyl iodide 1 afforded olefins.The reaction was found to proceed via the destannylsulfurization of the initially formed β-stannyl organosulfur compounds.Thus, allyl 2-pyridyl sulfides 2 or allyl phenyl sulfones 12 were converted into 1,3-dienes 4.Compounds 13 and 15 were converted into the olefins 14 and 17.Furthermore, the reaction was applied to the synthesis of α-substituted vinyl sulfides 24 and allene 27.The stereochemistry of the double bond is discussed.Keywords - destannylsulfurization; allyl 2-pyridyl sulfide; allyl phenyl sulfone; synthesis of olefin; 1,3-diene; vinyl sulfide; β-tributylstannyl organosulfur compound.
- Ochiai, Masahito,Ukita, Tatsuzo,Fujita, Eiichi,Tada, Shin-ichi
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p. 1829 - 1839
(2007/10/02)
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- A NEW SYNTHESIS OF 1,3-DIENES FROM ALLYL SULFIDES AND ALLYL SULFONES USING TRI-n-BUTYLSTANNYLMETHYL IODIDE
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Allyl 2-pyridyl sulfide 6 or allyl phenyl sulfone 7 on treatment with n-butyllithium in tetrahydrofuran followed by tri-n-butylstannylmethyl iodide (4) afforded directly the 1,3-diene 8 in good yield.
- Ochiai, Masahito,Tada, Shin-ichi,Sumi, Kenzo,Fujita, Eiichi
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p. 2205 - 2208
(2007/10/02)
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- SYNTHESIS OF TRANS-4,8,12,15,15-PENTAMETHYLBICYCLOPENTADECA-3E,7Z,12Z-TRIENE, A GEOMETRICAL ISOMER OF ANHYDROVERTICILLOL
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A 7Z-isomer of anhydroverticillol skeleton was constructed in 15 percent yield when the 7E allyl bromide having secoverticillol framework was treated with LiN(TMS)2.Reductive removal of the SO2Ph group furnished a geometrical isomer of anhydroverticillol.
- Kumagai, Takashi,Ise, Fumiaki,Uyehara, Tadao,Kato, Tadahiro
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- Stereoselective Synthesis of (+/-)-Irones
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β-, α-cis-, and α-trans-irones (1, 2a, and 2b) have been prepared via 2,5,6,6-tetramethyl-1-cyclohexene (7) and 1,4β,5,5-tetramethyl-6β-cyclohexene (8a) and its C-6 epimer (8b).Electrochemical epoxidation of
- Torii, Sigeru,Uneyama, Kenji,Matsunami, Setsuo
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