- Asymmetric Total Syntheses and Structure Revisions of Eurotiumide A and Eurotiumide B, and Their Evaluation as Natural Fluorescent Probes
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Asymmetric total syntheses and structure revisions of dihydroisocoumarin-type natural products, eurotiumide A and eurotiumide B have been described. The key features of these total syntheses are the asymmetric Shi epoxidation, regio- and stereoselective e
- Nakayama, Atsushi,Sato, Hideo,Karanjit, Sangita,Hayashi, Naoki,Oda, Masataka,Namba, Kosuke
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- Total synthesis of (+)-clavilactone A and (-)-clavilactone B by ring-opening/ring-closing metathesis
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The enantioselective total synthesis of natural enantiomers of clavilactones A and B has been achieved. A key feature of the synthesis is the use of a ring-opening/ring-closing metathesis, which allows the one-pot transformation of a strained cyclobutenecarboxylate into a γ-butenolide.
- Takao, Ken-Ichi,Nanamiya, Ryuki,Fukushima, Yuuki,Namba, Ayumi,Yoshida, Keisuke,Tadano, Kin-Ichi
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- Synthesis, cytotoxicity and pro-apoptosis activity of isoquinoline quinones
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Mansouramycins are newly isolated cytotoxic isoquinoline quinones from marine organism. To find novel anticancer agents, eighteen isoquinoline quinones 7a–7r as Mansouramycins analogs were designed and synthesized. Most of these compounds displayed modera
- Ni, Hua,Xia, Chao,Zhao, Yu
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- Concise syntheses of violaceoids A and C
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The concise syntheses of two alkylated hydroquinone natural products, violaceoids A and C, were accomplished by a protecting-group-free method employing the commercially available 2,5-dihydroxybenzal-dehyde as the starting material. The key strategy of the syntheses is the utilization of alkenylboronic acid as both the coupling and temporary protective reagents to efficiently introduce the requisite alkenyl side chain of violaceoid A. Moreover, the synthesis of violaceoid C is reported here for the first time.
- Narita, Koichi,Kimura, Ryuhei,Satoh, Hiroka,Watanabe, Kazuhiro,Yoshimura, Yuichi
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p. 232 - 235
(2021/02/06)
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- Total synthesis of the aglycone of IB-00208
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Abstract A total synthesis of the aglycone of IB-00208 was accomplished in 22 steps using a newly developed approach towards polycyclic 1,4-dioxygenated xanthones from benzocyclobutenones. The generality of this entry to xanthones was initially established on several model systems before it was successfully applied to the construction of the hexacyclic core of the natural product. A new and potentially general approach towards angularly fused benzocyclobutenones using ring-closing metathesis (RCM) was also developed.
- Knueppel, Daniel,Yang, Jingyue,Cheng, Bo,Mans, Douglas,Martin, Stephen F.
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p. 5741 - 5757
(2015/08/03)
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- HCV PROTEASE INHIBITORS
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The present invention discloses a compound of general formula (I); A is O, S, CH, NH or NR', when O links with Z3, Z1 is N or CRZ1, Z2 is CRZ2, when Z1 links with O, Z2 is CH, Z3 is C-Ar; Ra, Rb, Rc and Rd independently is H, OH, halogen or -Y1-Rm; A1 is NH or CH2; R1' is alkyl, aryl, cycloalkyl, heterocycloalkyl or heteroaryl; A2 is N, O or linking bond; R1 is hydrogen, or, R1 linking covalently with R3 forms C5-C9 saturated or unsaturated hydrocarbon chain substituted by O or N; R3 is alkyl, cycloalkyl, heterocycloalkyl, alkyl substituted by cycloalky etc; R4 is alkoxy-CO, alkyl-NHCO, (alkyl)2NCO, or formyl substituted by aryl, cycloalkyl, heterocycloalkyl.
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Paragraph 0092; 0093
(2014/06/24)
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- HCV Protease Inhibitors
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A compound of general formula (I); A is O, S, CH, NH or NR′, when O links with Z3, Z1 is N or CRZ1, Z2 is CRZ2, when Z1 links with O, Z2 is CH, Z3 is C—Ar; Ra, Rb, Rc and Rd independently is H, OH, halogen or —Y1—Rm; A1 is NH or CH2; R1′ is alkyl, aryl, cycloalkyl, heterocycloalkyl or heteroaryl; A2 is N, O or linking bond; R1 is hydrogen, or, R1 linking covalently with R3 forms C5-C9 saturated or unsaturated hydrocarbon chain substituted by O or N; R3 is alkyl, cycloalkyl, heterocycloalkyl, alkyl substituted by cycloalkyl etc; R4 is alkoxy-CO, alkyl-NHCO, (alkyl)2NCO, or formyl substituted by aryl, cycloalkyl, heterocycloalkyl.
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Paragraph 0198-0200
(2014/06/24)
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- Total syntheses of graphisin A and sydowinin B
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Efficient syntheses of the highly substituted benzophenone graphisin A and the xanthone sydowinin B are described. Key steps involve aryl anion addition to substituted benzaldehyde derivatives, subsequent methyl ester installation, and dehydrative cycliza
- Little, Andrew,Porco, John A.
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supporting information; experimental part
p. 2862 - 2865
(2012/07/17)
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- Synthetic studies toward (+)-cortistatin A
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We describe herein the synthesis of a late-stage intermediate en route to cortistatin A. Key transformations included a Snieckus-like cascade sequence culminating in a 6π-electrocyclization, an alkylative dearomatization, and the stereoselective functiona
- Wang, Zhang,Dai, Mingji,Park, Peter K.,Danishefsky, Samuel J.
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scheme or table
p. 10249 - 10260
(2012/01/05)
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- Sporolide B: Synthetic studies
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Studies directed toward the synthesis of the architecturally complex marine natural product sporolide B are described. Synthetic analysis suggested advanced hydroquinone and benzodiquinane fragments, which upon elaboration were successfully united via an
- Gladding, Jeffery A.,Bacci, James P.,Shaw, Scott A.,Smith III, Amos B.
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scheme or table
p. 6697 - 6706
(2011/10/01)
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- Total synthesis of (±)-aspercyclide A and its C19 methyl ether
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The total syntheses of (±)-aspercyclide A (1) and its C19 methyl ether (15a) featuring Heck-Mizoroki macrocyclisation to form the 11-membered (E)-styrenyl biaryl ether lactone core are described. The Royal Society of Chemistry 2010.
- Carr, James L.,Offermann, Daniel A.,Holdom, Mary D.,Dusart, Philip,White, Andrew J. P.,Beavil, Andrew J.,Leatherbarrow, Robin J.,Lindell, Stephen D.,Sutton, Brian J.,Spivey, Alan C.
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supporting information; experimental part
p. 1824 - 1826
(2010/06/15)
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- Total synthesis of the aspercyclides
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Two different approaches to the eleven-membered biaryl ether lactones of the aspercyclide family are disclosed. The core regions of these highly strained targets, which are able to interfere with the binding of immunoglobulinE to its high affinity receptor, can either be forged by ring-closing olefin metathesis (RCM) or by a highly diastereoselective chromium-mediated Nozaki-Hiyama-Kishi (NHK) reaction. Whereas the RCM approach turned out to be responsive to minor changes in the substitution pattern of the substrate, the NHK route is more generally applicable. The preparation of the required cyclization precursor 43 hinged on a palladium-catalyzed orthoiodination reaction of 2-methylbenzoic acid, an efficient copper-catalyzed Ullmann coupling, and a Takai-Utimoto olefination as the key steps. Moreover, the esterification of the 2,6-disubstituted benzoic acid 34 with the sterically hindered secondary alcohol 37 was far from trivial. However, this and related transformations were accomplished by recourse to the corresponding acid fluorides, which provided excellent yields in cases in which the more commonly used acid chlorides or mixed anhydrides failed to afford any of the desiredproducts.
- Pospisil, Jiri,Mueller, Christoph,Fuerstner, Alois
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experimental part
p. 5956 - 5968
(2010/03/03)
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- Active core structure of terfestatin A, a new specific inhibitor of auxin signaling
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The auxins, plant hormones, regulate many aspects of the growth and development of plants. Terfestatin A (TrfA), a novel auxin signaling inhibitor, was identified in a screen of Streptomyces sp. F40 extracts for inhibition of the expression of an auxin-in
- Hayashi, Ken-ichiro,Yamazoe, Atsushi,Ishibashi, Yuki,Kusaka, Naoyuki,Oono, Yutaka,Nozaki, Hiroshi
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p. 5331 - 5344
(2008/12/20)
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- Total synthesis of bioactive frustulosin and frustulosinol
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Stereum hirsutum is a pathogenic fungus involved in 'Esca', a trunk wood disease of grapevine. Among the metabolites isolated from the culture medium of this fungus, frustulosin (2a) shows a high phytotoxicity. A new simple and efficient method for the sy
- Goddard, Mary-Lorène,Tabacchi, Raffaele
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p. 909 - 911
(2007/10/03)
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- Disubstituted lavendustin a analogs and pharmaceutical compositions comprising the analogs
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Disubstituted lavendustin A analogs that are PTK inhibitors having antiproliferative activity are described. Preferred compounds of the present invention, without limitation, satisfy either Formula 1 or Formula 2. Currently preferred compounds ,based on in vivo biological activity, are 4'-adamantylbenzoate-1'-N-1,4-dihydroxybenzylamine and 4'-adamantylmethylbenzoate-1'-N-1,4-dihydroxybenzylamine. The present invention also provides pharmaceutical compositions comprising effective amounts of disubstituted lavendustin A analogs. Such compositions also may comprise other active ingredients, other materials conventionally used in the formulation of pharmaceutical composition, and mixtures thereof. The compounds and compositions of the present invention can be used for treating subjects to, for example, inhibit the proliferation of living cells in the treatment of proliferative diseases.
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- Total synthesis of the quinone epoxide dimer (+)-torreyanic acid: Application of a biomimetic oxidation/electrocyclization/Diels-Alder dimerization cascade
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An asymmetric synthesis of the quinone epoxide dimer (+)-torreyanic acid (48) has been accomplished employing [4 + 2] dimerization of diastereomeric 2H-pyran monomers. Synthesis of the related monomeric natural product (+)-ambuic acid (2) has also been achieved which establishes the biosynthetic relationship between these two natural products. A tartrate-mediated nucleophilic epoxidation involving hydroxyl group direction facilitated the asymmetric synthesis of a key chiral quinone monoepoxide intermediate. Thermolysis experiments have also been conducted on a model dimer based on the torreyanic acid core structure and facile retro Diels-Alder reaction processes and equilibration of diastereomeric 2H-pyrans have been observed. Theoretical calculations of Diels-Alder transition states have been performed to evaluate alternative transition states for Diels-Alder dimerization of 2H-pyran quinone epoxide monomers and provide insight into the stereocontrol elements for these reactions.
- Li, Chaomin,Johnson, Richard P.,Porco Jr., John A.
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p. 5095 - 5106
(2007/10/03)
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- Exploring Chemical Diversity of Epoxyquinoid Natural Products: Synthesis and Biological Activity of (-)-Jesterone and Related Molecules
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(matrix presented) Enantioselective syntheses of the potent antifungal agent (-)-jesterone, its hydroxy epimer, and a dimeric quinone epoxide derivative are reported. The synthesis involves diastereoselective epoxidation of a chiral quinone monoketal deri
- Hu, Yongbo,Li, Chaomin,Kulkarni, Bheemashankar A.,Strobel, Gary,Lobkovsky, Emil,Torczynski, Richard M.,Porco Jr., John A.
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p. 1649 - 1652
(2007/10/03)
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