- Understanding the conformational analysis of gababutin based hybrid peptides
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Constrained γ-amino acid gababutin (Gbn) based peptides that form different conformations have been synthesized. Striving to rationalize the impact of side chain orientations framing tetrapeptide-based supramolecular organic frameworks and morphological entities, Gbn incorporated hybrid peptides Boc-Gbn-Aib-Aaa-Aib-OMe (where Aaa = Phe(F) for peptide 1, Leu(L) for peptide 2 and Tyr(Y) for peptide 3) were synthesized by changing the amino acid at the third position. The solution state dual folded conformation (C12/C10 H-bonded) is probed by 2D NMR spectroscopy in support of a DMSO-d6 titration and VT NMR experiments. Peptides 1-3 adopt a C12/C10 type H-bonded dual folded conformation in the crystal state. In addition, distinct supramolecular frameworks result from the modification and orientation of the third residue side chain of peptides 1-3. A solvent induced morphological diversity of peptides 1-3 is attained by modifying the side chain backbone of the tetrapeptides, which are investigated by various microscopic (SEM and AFM) studies. Gbn-based peptides 1-3 show significant morphological and supramolecular packing properties, which are fairly different from those of their gabapentin (Gpn) based analogue peptides.
- Konda, Maruthi,Jadhav, Rohit G.,Maiti, Sayan,Mobin, Shaikh M.,Kauffmann, Brice,Das, Apurba K.
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Read Online
- Synthesis and Exploration of Abscisic Acid Receptor Agonists Against Dought Stress by Adding Constraint to a Tetrahydroquinoline-Based Lead Structure
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New oxotetrahydroquinolinyl- and oxindolinyl sulfonamides interacting with RCAR/(PYR/PYL) receptor proteins were identified as lead structures against drought stress in crops starting from protein docking studies of a sulfonamide lead structure, followed by in-depth SAR studies. Optimized five to six step synthetic approaches via substituted amino oxo-tetrahydro-quinolines and amino oxo-indolines as essential intermediates gave access to the envisaged oxo-tetrahydroquinolinyl and oxindolinyl sulfonamides. Whilst oxo-tetrahydroquinolinyl sulfonamides with additional carbon substituents or spiro-cycloalkyl groups exhibited only low to moderate target affinities, the corresponding spiro-oxindolinyl and oxo-tetrahydroquinolinyl sulfonamides carrying optimized N-substituents revealed strong interactions with RCAR/(PYR/PYL) receptor proteins in Arabidopsis thaliana. Remarkably, the in vitro activity observed for these new compounds was on the same level as observed for the naturally occurring plant hormone in line with strong efficacy against drought stress in-vivo (canola and wheat as broad-acre crops).
- Baltz, Rachel,Bojack, Guido,Dittgen, Jan,Fischer, Christian,Frackenpohl, Jens,Freigang, J?rg,Getachew, Rahel,Grill, Erwin,Helmke, Hendrik,Hohmann, Sabine,Lange, Gudrun,Lehr, Stefan,Porée, Fabien,Schmidt, Jana,Schmutzler, Dirk,Yang, Zhenyu
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supporting information
p. 3442 - 3457
(2021/06/25)
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- INHIBITORS OF MICROBIALLY INDUCED AMYLOID
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The present disclosure provides compounds useful for the prevention of amyloid formation and the treatment of amyloid related disorders, including synucleopathies such as Parkinson's Disease.
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Paragraph 0001032-0001033
(2021/07/17)
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- Visible-Light Mediated Hydrosilylative and Hydrophosphorylative Cyclizations of Enynes and Dienes
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Described herein is a visible-light mediated intermolecular radical cyclization approach to access heterocycles. Heteroatom radicals, such as silicon and phosphorus atom radicals, were generated via direct hydrogen atom abstraction by the photoexcited catalyst species with hydro-silanes and phosphine oxides. The radical addition/cyclization/HAT (hydrogen atom transfer) reaction sequences of 1,6-enynes and 1,6-dienes were highly efficient delivering the desired heterocycles in good yields.
- Chen, Xiaoyun,Hou, Hong,Shi, Yaocheng,Xu, Yue,Yan, Chaoguo,Yang, Haibo,Zhu, Shaoqun
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supporting information
(2020/03/04)
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- Visible-Light-Promoted Intramolecular α-Allylation of Aldehydes in the Absence of Sacrificial Hydrogen Acceptors
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We report herein an unprecedented protocol for radical cyclization of aldehydes with pendant alkenes via synergistic photoredox, cobaloxime, and amine catalysis. The transformation was achieved in the absence of external oxidants, providing a variety of 5-, 6-, and 7-membered ring products with alkene transposition in satisfactory yields. The reaction exhibits wide functional group compatibility and occurs under mild conditions with extrusion of H2.
- Liu, Feng,Liu, Jia-Li,tu, Jia-Lin
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supporting information
p. 7369 - 7372
(2020/10/05)
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- Synthesis of novel shikonin derivatives and pharmacological effects of cyclopropylacetylshikonin on melanoma cells
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Despite much research in the last centuries, treatment of malignant melanoma is still challenging because of its mostly unnoticeable metastatic spreading and aggressive growth rate. Therefore, the discovery of novel drug leads is an important goal. In a previous study, we have isolated several shikonin derivatives from the roots of Onosma paniculata Bureau & Franchet (Boraginaceae) which evolved as promising anticancer candidates. β,β-Dimethylacrylshikonin (1) was the most cytotoxic derivative and exhibited strong tumor growth inhibitory activity, in particular, towards melanoma cells. In this study, we synthesized eighteen novel shikonin derivatives in order to obtain compounds which exhibit a higher cytotoxicity than 1. We investigated their cytotoxic potential against various melanoma cell lines and juvenile skin fibroblasts. The most active compound was (R)-1-(1,4-dihydro-5,8-dihydroxy-1,4-dioxonaphthalen-2-yl)-4-methylpent-3-enyl cyclopropylacetate (cyclopropylacetylshikonin) (6). It revealed significant stronger tumor growth inhibitory activity towards two melanoma cell lines derived from metastatic lesions (WM164 and MUG-Mel2). Further investigations have shown that 6 induced apoptosis caspase-dependently, increased the protein levels of cleaved PARP, and led to double-stranded DNA breaks as shown by phosphorylation of H2AX. Cell membrane damage and cell cycle arrest were not observed.
- Durchschein, Christin,Bauer, Rudolf,Kretschmer, Nadine,Hufner, Antje,Rinner, Beate,Stallinger, Alexander,Deutsch, Alexander,Lohberger, Birgit
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supporting information
(2018/11/23)
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- USE OF SUBSTITUTE OXO TETRAHYDROQUINOLINE SULFONAMIDES OR SALTS THEREOF FOR RAISING STRESS TOLERANCE OF PLANTS
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The invention relates to the use of substituted oxotetrahydroquinolinylsulfonamides or salts thereof where the radicals in the general formula (I) correspond to the definitions given in the description, for enhancing stress tolerance in plants to abiotic stress, and/or for increasing plant yield.
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Paragraph 0199
(2017/02/28)
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- Copper-Catalyzed Enantio-, Diastereo-, and Regioselective [2,3]-Rearrangements of Iodonium Ylides
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The first highly enantioselective, diastereoselective, and regioselective [2,3]-rearrangement of iodonium ylides has been developed as a general solution to catalytic onium ylide rearrangements. In the presence of a chiral copper catalyst, substituted allylic iodides couple with α-diazoesters to generate metal-coordinated iodonium ylides, which undergo [2,3]-rearrangements with high selectivities (up to >95:5 r.r., up to >95:5 d.r., and up to 97 % ee). The enantioenriched iodoester products can be converted stereospecifically into a variety of onium ylide rearrangement products, as well as compounds that are not accessible by classical onium ylide rearrangements.
- Xu, Bin,Tambar, Uttam K.
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supporting information
p. 9868 - 9871
(2017/08/08)
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- The synthesis of α,α-disubstituted α-amino acids via ichikawa rearrangement
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An approach to α,α-disubstituted α-amino acids is reported. The key step is allyl cyanate-to-isocyanate rearrangement. As demonstrated, the resultant allyl isocyanates can be directly trapped with various nucleophiles, for instance, alcohols, amines, and organometallic reagents, to provide a broad range of N-functionalized allylamines. The developed method has been successfully applied in the synthesis of two bioactive peptides: 2-aminoadamantane-2-carboxylic acid derived P2X7-evoked glutamate release inhibitor and 4-amino-tetrahydropyranyl-4-carboxylic acid derived dipeptide GSK-2793660, which is currently in clinical trials as cathepsin C inhibitor for the treatment of cystic fibrosis, noncystic fibrosis bronchiectasis, ANCA-associated vasculitis and bronchiectasis.
- Szczes?niak, Piotr,Pieczykolan, Micha?,Stecko, Sebastian
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p. 1057 - 1074
(2016/02/19)
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- Titanium(IV) Chloride-Mediated Stereoselective α-Alkylidenation to Efficiently Assemble Multisubstituted 1,3-Dienes
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A direct access to multisubstituted 1,3-dienes by α-exclusive alkylidenation of crotonic derivatives has been developed. This protocol, mediated by titanium tetrachloride chelation, features excellent regio- and stereoselectivity, mild reaction conditions, easy operation and wide substrate scope. Conversions of the derived dienes to other useful molecules were also explored. (Figure presented.).
- Sun, Rengwei,Song, Wei,Ma, Chunmei,Zhang, Huiwen,Yu, Xinhong
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supporting information
p. 3977 - 3982
(2016/12/30)
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- Protected amino hydroxy adamantane carboxylic acid and process for its preparation
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Dipeptidyl peptidase IV (DP 4) inhibiting compounds are provided. The provided compounds can be used for treating diabetes and related diseases, especially Type II diabetes, and other diseases as set out herein, employing such DP 4 inhibitor or a combination of such DP 4 inhibitor and one or more of another antidiabetic agent such as metformin, glyburide, troglitazone, pioglitazone, rosiglitazone and/or insulin and/or one or more of a hypolipidemic agent and/or anti-obesity agent and/or other therapeutic agent.
- -
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Paragraph 0215
(2015/11/24)
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- SUBSTITUTED PYRIMIDINE COMPOUNDS, COMPOSITIONS AND MEDICINAL APPLICATIONS THEREOF
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The present disclosure relates to pyrimidine compounds of formula (I), their stereoisomers, tautomers, pharmaceutically acceptable salts, polymorphs, solvates, and hydrates thereof. The present disclosure also relates to process of preparation of these pyrimidine compounds, and to pharmaceutical compositions containing them. The compounds of the present disclosure are useful in the treatment, prevention or suppression of diseases and disorders mediated by epidermal growth factor receptor (EGFR) family kinases.
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Paragraph 000147
(2015/03/13)
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- Isothiourea-mediated asymmetric functionalization of 3-alkenoic acids
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Isothiourea HBTM-2.1 promotes the catalytic asymmetric α- functionalization of 3-alkenoic acids through formal [2 + 2] cycloadditions with N-tosyl aldimines and formal [4 + 2] cycloadditions with either 4-aryltrifluoromethyl enones or N-aryl-N-aroyl diazenes, providing useful synthetic building blocks in good yield and with excellent enantiocontrol (up to >99% ee). Stereodefined products are amenable to further synthetic elaboration through manipulation of the olefinic functionality.
- Morrill, Louis C.,Smith, Samuel M.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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p. 1640 - 1655
(2014/03/21)
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- USE OF CONDENSED BENZO[B]THIAZINE DERIVATIVES AS CYTOPROTECTANTS
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The present invention relates to arylthiazine compounds, metabolites, N-oxides, amides, esters,pharmaceutically acceptable salts, hydrates and solvates thereof and their use as cytoprotectants in the treatment or prophylaxis of diseases or states, either acute or chronic, involving aberrant cellular lipid peroxidation in the central nervous system or in the periphery of the body. The present invention also relates to a method for their preparation and to pharmaceutical composition comprising as an active ingredient one or more of the aforementioned compounds.
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Page/Page column 60
(2014/12/12)
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- Enantioselective intramolecular aldehyde α-alkylation with simple olefins: Direct access to homo-ene products
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A highly selective method for the synthesis of asymmetrically substituted carbocycles and heterocycles from unactivated aldehyde-olefin precursors has been achieved via enantioselective SOMO-catalysis. Addition of a catalytically generated enamine radical cation across a pendent olefin serves to establish a general asymmetric strategy toward the production of a wide range of formyl-substituted rings with alkene transposition. Conceptually, this novel mechanism allows direct access to "homo-ene"-type products.
- Comito, Robert J.,Finelli, Fernanda G.,Macmillan, David W. C.
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supporting information
p. 9358 - 9361
(2013/07/26)
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- Catalytic, enantioselective, and highly chemoselective bromocyclization of olefinic dicarbonyl compounds
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Overriding preferences: An amine-thiocarbamate catalyst can mediate the facile, efficient, and highly enantioselective bromocyclization of olefinic 1,3-dicarbonyl compounds. In the presence of the bifunctional catalyst, the bromination occurs chemoselectively at the olefinic moiety rather than at the carbon atom in the α-position to the carbonyl units. Copyright
- Zhao, Yi,Jiang, Xiaojian,Yeung, Ying-Yeung
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supporting information
p. 8597 - 8601
(2013/09/12)
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- A newly-designed PE-supported arsine for efficient and practical catalytic Wittig olefination
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A newly designed PE-supported arsine has been developed as an excellent catalyst for catalytic Wittig-type olefination. Simple ketones, in particular inactive ketones prove to be suitable substrates for the first time. This reaction provides an easy access to di-, tri-, and tetra-substituted olefins in high yield.
- Wang, Peng,Liu, Chun-Rong,Sun, Xiu-Li,Chen, Shuai-Shuai,Li, Jun-Fang,Xie, Zuowei,Tang, Yong
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supporting information; experimental part
p. 290 - 292
(2012/01/06)
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- α,β-Unsaturated imines via Ru-catalyzed coupling of allylic alcohols and amines
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A convenient synthesis of α,β-unsaturated imines requiring only an allylic alcohol, an amine and a Ru catalyst has been developed. The use of large excesses of oxidant and the purification of sensitive intermediates can be avoided.
- Rigoli, Jared W.,Moyer, Sara A.,Pearce, Simon D.,Schomaker, Jennifer M.
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supporting information; experimental part
p. 1746 - 1749
(2012/04/23)
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- Synthesis and biological activity of permethrinic acid analogs containing various substituents in position 2 of the cyclopropane ring
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A number of permethrinic acid ethyl ester derivatives having various substituents [Et, Pr, Ph, Ph(CH2) n (n = 1, 2), etc.] in position 2 of the cyclopropane ring were synthesized, and their insecticidal acivity against typhoid flies, rice weevils, and bean aphides, as well as juvenoid activity on flour beetle chrysalises, was studied. The newly synthesized compounds turned out to exhibit weak insecticidal activity against standard insects but pronounced juvenile hormone activity, which differentiates them from permethrinic acid esters.
- Mirzabekova,Kuz'mina,Lukashov,Sokolova,Golosov,Kazakov,Perlova,Potapova,Kheinman,Ivanova
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experimental part
p. 1139 - 1149
(2009/09/25)
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- Umpolung of Michael acceptors catalyzed by N-heterocyclic carbenes
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N-Heterocyclic carbenes can catalyze β-alkylations of a range of α,β-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic β carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence. Copyright
- Fischer, Christian,Smith, Sean W.,Powell, David A.,Fu, Gregory C.
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p. 1472 - 1473
(2007/10/03)
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- Microwave-assisted regioselective olefinations of cyclic mono- and di-ketones with a stabilized phosphorus ylide
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A number of cyclic mono- and di-ketones underwent regioselective olefination with (carbethoxyethylidene)triphenylphospharane under controlled microwave heating. The Wittig reaction of 4-substituted cyclohexanones or 1,2- and 1,4-cyclohexanediones with the ylide at 190 °C for 20 min in MeCN afforded the exocyclic olefins in >94:6 isomer ratios. On the other hand, the same reactions carried out at 230 °C for 20 min in the presence of 20 mol % DBU furnished the endocyclic olefins in >83:17 isomer ratios. The base-mediated isomerization of the exocyclic olefins into the endocyclic isomers was primarily driven by thermodynamic stability of the products and the effect of ring structures on deconjugation was examined.
- Wu, Jinlong,Li, Dan,Wu, Huafeng,Sun, Lijie,Dai, Wei-Min
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p. 4643 - 4650
(2007/10/03)
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- New application of bromotrimethylsilane: Elaboration of aldehydes/ketones into homologous α,β-unsaturated esters via β-hydroxy esters
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α,β-Unsaturated esters are formed when β-hydroxy esters react with bromotrimethylsilane which is generated from chlorotrimethylsilane- lithium bromide in acetonitrile. Copyright Taylor & Francis, Inc.
- Suri, Suresh C.,Marcischak, Jacob C.
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p. 379 - 387
(2007/10/03)
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- Discovery and preclinical profile of saxagliptin (BMS-477118): A highly potent, long-acting, orally active dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes
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Efforts to further elucidate structure-activity relationships (SAR) within our previously disclosed series of β-quaternary amino acid linked L-cis-4,5-methanoprolinenitrile dipeptidyl peptidase IV (DPP-IV) inhibitors led to the investigation of vinyl substitution at the β-position of α-cycloalkyl-substituted glycines. Despite poor systemic exposure, vinyl-substituted compounds showed extended duration of action in acute rat ex vivo plasma DPP-IV inhibition models. Oxygenated putative metabolites were prepared and were shown to exhibit the potency and extended duration of action of their precursors in efficacy models measuring glucose clearance in Zuckerfa/fa rats. Extension of this approach to adamantylglycine- derived inhibitors led to the discovery of highly potent inhibitors, including hydroxyadamantyl compound BMS-477118 (saxagliptin), a highly efficacious, stable, and long-acting DPP-IV inhibitor, which is currently undergoing clinical trials for treatment of type 2 diabetes.
- Augeri, David J.,Robl, Jeffrey A.,Betebenner, David A.,Magnin, David R.,Khanna, Ashish,Robertson, James G.,Wang, Aiying,Simpkins, Ligaya M.,Taunk, Prakash,Huang, Qi,Han, Song-Ping,Abboa-Offei, Benoni,Cap, Michael,Xin, Li,Tao, Li,Tozzo, Effie,Welzel, Gustav E.,Egan, Donald M.,Marcinkeviciene, Jovita,Chang, Shu Y.,Biller, Scott A.,Kirby, Mark S.,Parker, Rex A.,Hamann, Lawrence G.
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p. 5025 - 5037
(2007/10/03)
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- Fluoro-olefins as peptidomimetic inhibitors of dipeptidyl peptidases
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The feasibility of the fluoro-olefin function as a peptidomimetic group in inhibitors for dipeptidyl peptidase IV and II (DPP IV and DPP II) is investigated by evaluation of N-substituted Gly-Ψ[CF=C]pyrrolidines, Gly-Ψ[CF=C]piperidines, and Gly-Ψ[CF=C](2-cyano)pyrrolidines. Of this later class, the (Z)- and (E)-fluoro-olefin analogues were prepared and chemical stability in comparison with the parent amide was checked. Most of these compounds exhibited a strong binding preference toward DPP II with IC 50 values in the low micromolar range, while only low DPP IV inhibitory potential is seen.
- Van Der Veken, Pieter,Senten, Kristel,Kertèsz, István,De Meester, Ingrid,Lambeir, Anne-Marie,Maes, Marie-Berthe,Scharpé, Simon,Haemers, Achiel,Augustyns, Koen
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p. 1768 - 1780
(2007/10/03)
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- Acid-promoted olefination of ketones by an iron(III) porphyrin complex
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(Matrix presented) The acid-promoted olefination of unactivated ketones with diazo reagents in the presence of triphenylphosphine can be catalyzed by the commercially available iron(III) porphyrin complex Fe(TPP)Cl. The reactions were effectively carried out under mild conditions in a one-pot fashion with the use of a stoichiometric diazo reagents and substoichiometric benzoic acid. Examples include aromatic, aliphatic, cyclic, and unsaturated ketones with ethyl diazoacetate or tert-butyl diazoacetate.
- Chen, Ying,Huang, Lingyu,Zhang, X. Peter
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p. 2493 - 2496
(2007/10/03)
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- Cyclopropyl-fused pyrrolidine-based inhibitors of dipeptidyl peptidase IV and method
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Dipeptidyl peptidase IV (DP 4) inhibiting compounds are provided having the formula where x is 0 or 1 and y is 0 or 1 (provided that x=1 when y=0 and x=0 when y=1); n is 0 or 1; X is H or CN; and wherein R1, R2, R3 and R4 are as described herein. A method is also provided for treating diabetes and related diseases, especially Type II diabetes, and other diseases as set out herein, employing such DP 4 inhibitor or a combination of such DP 4 inhibitor and one or more of another antidiabetic agent such as metformin, glyburide, troglitazone, pioglitazone, rosiglitazone and/or insulin and/or one or more of a hypolipidemic agent and/or anti-obesity agent and/or other therapeutic agent.
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- Claisen rearrangement based methodology for the spiroannulation of a cyclopentane ring. Formal total synthesis of (±)-acorone and isoacorones
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A Claisen rearrangement based methodology for spiroannulation of a cyclopentane ring to cyclic precursors and its application in the formal total synthesis of acorones 1 is described. Thus, Claisen rearrangement of 2-cycloalkylideneethanols 12 with 2-methoxypropene and a catalytic amount of mercuric acetate generates 4,4-substituted hex-5-en-2-ones 13. Ozonolytic cleavage of the terminal olefin in the enones 13 and intramolecular aldol condensation of the resulting keto-aldehydes 14 furnishes the spiroannulated compounds 15. (C) 2000 Elsevier Science Ltd.
- Srikrishna,Praveen Kumar
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p. 8189 - 8195
(2007/10/03)
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- Cascade rearrangement of spiroepoxymethyl radicals into 2-oxocycloalkyl radicals: Evaluation of a two-carbon cycloalkanone ring expansion
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Series of 2-bromomethyl- and 2-hydroxymethyl-1-oxaspiro[2.n]alkanes were prepared from cycloalkanones by initial Wadsworth-Horner-Emmons methodology to afford ester-substituted methylenecycloalkanes. The latter were selectively reduced to hydroxymethylmethylenecycloalkanes which were epoxidised with peroxyacetic acid. Homolytic reactions were studied by EPR spectroscopy which enabled transient 3-oxoalk-1-enyl radicals, and their cyclisation products, 2-oxocycloalkyl and 2-oxocycloalkylmethyl radicals, to be characterised. This evidence, together with end product analyses of organotin hydride reductions of the 2-bromomethyl-1-oxaspiro[2.n]alkanes, established that the initial spiroepoxymethyl radicals rearranged by a three-stage cascade of two consecutive β-scissions followed by a cyclisation. Cyclisations of the 3-oxoalk-1-enyl radicals took place mainly in the endo-mode to afford 2-oxocycloalkyl radicals, except for the 5-oxohept-6-enyl radical for which exo-cyclisation to generate the 2-oxocyclohexylmethyl radical was preferred. Kinetic data for the exo-and endo-cyclisations of the 4-oxohex-5-enyl radical were obtained from tributyltin hydride mediated reactions of 2-bromomethyl-1-oxaspiro[2.3]hexane.
- Afzal, Mohammad,Walton, John C.
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p. 937 - 945
(2007/10/03)
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- Obtention of 2,2-(diethoxy) vinyl lithium and 2-methyl-4-ethoxy butadienyl lithium by Arene-catalysed lithiation of the corresponding chloro derivatives. Synthetic applications
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Vinylic lithium reagents 1 and 2 could be obtained by the title procedure from their chloro precursors 5 and 6 instead of the less stable corresponding bromo derivatives 3 and 4. Condensation with carbonyl compounds leads to interesting synthetic applications such as a two steps synthesis of retinal 13 from β-cyclocitral 10.
- Si-Fodil, Mohamed,Ferreira, Humberto,Gralak, Jean,Duhamel, Lucette
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p. 8975 - 8978
(2007/10/03)
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- Intramolecular cyclization of 2,7- or 2,8-bis-unsaturated esters mediated by (η2-propene)Ti(O-i-Pr)2. Facile construction of mono- and bicyclic skeletons with stereoselective introduction of a side chain. A synthesis of d-sabinene
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tert-Butyl 2-en-7-ynoate 6 was treated with (η2-propene)Ti(O-i-Pr)2 (3), generated in situ from Ti(O-i-Pr)4 or Ti(O-i-Pr)3Cl and i-PrMgCl, in ether at -50 to -20°C to afford the product 8 in good yield. The presence of the intermediate titanabicycle 7 was verified by bis-deuterolysis with excess D2O. When the titanabicycle 7 was treated with 1.1 equiv of i-PrOD and then worked up as usual, the monodeuterated product 10 was obtained with high sight selectivity and stereoselectivity. Other electrophiles such as aldehydes and ketones also reacted with the titanabicycle in a highly stereoselective manner to give cyclopentanes having a stereo-defined side chain. On the contrary, treatment of the corresponding ethyl ester, ethyl 8-(trimethylsilyl)-(E)-2-octen-7-ynoate (28), with 3 under the same conditions followed by the addition of 1.1 equiv of s-BuOH afforded 2-(trimethylsilyl)-1-bicyclo[3.3.0]- octen-3-one (32) in 80% yield. Quenching the same reaction mixture with i-PrOD, EtCHO, and Et2CO in place of s-BuOH gave 4-deuterio (with exclusive deuterium incorporation), 4-(1-hydroxypropyl), and 4-(1-ethyl-1-hydroxypropyl) derivatives of the above bicyclic ketone (34, 35, and 36) in good yields. These electrophiles were always introduced from the convex face of the bicyclic skeleton. The stereochemistry of the cyclization could be controlled by an allylic substituent such as (tert-butyl)dimethylsiloxy or butyl group to a high degree yet with a reversal diastereoselection to give 45 or 47. The reaction of ethyl 7-octen-2-ynoate (56) and 3 at -50 to 0°C took place in a quite different way to afford 1-[(ethoxycarbonyl)methyl]bicyclo[3.1.0]hexane (64) in 74% yield after hydrolysis. If the simple hydrolysis is replaced by deuterolysis or the action of diethylketone, 1-[(ethoxycarbonyl)dideuteriomethyl] (with 99% deuterium incorporation), or 1-[(ethoxycarbonyl)(3-pentylidene)methyl] derivative of the above product (65 or 66) was obtained in good yields. A 7-en-2-ynoate having an internal Z-double bond such as 80 afforded a single stereoisomer 82 with the substituent at the endo position, of the bicyclic skeleton, suggesting that the stereochemical integrity of the Z-double bond of the starting material was retained in the product. An alkyl substituent at the allylic position of the substrates like 74 and 76 nicely controlled the stereochemistry of the cyclization to afford single products 75 and 77 with the substituent being placed in the exo orientation of the bicyclic structure. This high diastereoselectivity was successfully applied to an enantioselective synthesis of d-sabinene from an optically active enynoate via nearly complete chirality transfer.
- Urabe,Suzuki,Sato
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p. 10014 - 10027
(2007/10/03)
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- 2,2-Di(ethoxy)vinyllithium: Reactions with carbonyl compounds
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2,2-Di(ethoxy)vinyllithium 2 generated from bromo ketene acetal 1 reacts with carbonyl compounds to give either β-hydroxy esters 5 or conjugated esters 6 or hydroxy ketene acetals 7 according to the work up.
- Hiouni, Abdelaziz,Duhamel, Lucette
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p. 5507 - 5510
(2007/10/03)
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- A simple strategy for spirocyclopentannulation of cyclic ketones. Formal total synthesis of (±)-acorone
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A general and simple methodology for spirocyclopentannulation of cyclic ketones (or 4,4-disubstituted cyclopentenones from acyclic ketones) and its application in the synthesis of the spirodienone 7 via a prochiral precursor constituting a formal total synthesis of (±)-acorone (6), are described.
- Srikrishna, Adusumilli,Kumar, P. Praveen,Viswajanani, Ranganathan
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p. 1683 - 1686
(2007/10/03)
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- N-SUBSTITUTED HETEROCYCLIC DERIVATIVES, THEIR PREPARATION AND THE PHARMACEUTICAL COMPOSITIONS IN WHICH THEY ARE PRESENT
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The invention relates to N-substituted heterocyclic derivatives and its salts. These derivatives have the formula (I) in which the substituents are as defined in the specification. Application: Angiotensin II antagonists
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- Structural Effects on the RhII-Catalyzed Rearrangement of Cyclopropenes
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The termocatalytic rearrangement of 2-alkylcycloprop-2-ene-1-carboxylates (1) in the presence of RhII perfluorobutyrate is regio- and stereospecific and leads to the less substituted metallocarbenes 3.The latter undergo intramolecular C-H bond insertion to form cyclopentylidenes (4).In contrast, the metallocarbenes 19, derived from 2,3-dialkylcycloprop-2-ene-1-carboxylates 6c, d, react to dienes (Z)-20, via 1,2-H migration.The cyclopropenedicarboxylates 10, in turn, rearrange exclusively to the more substituted metallocarbene 26, which cyclize to furans 28.With 6e and 12, products derived from both modes of ring-opening are observed.
- Mueller, Paul,Graenicher, Christian
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p. 521 - 534
(2007/10/02)
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- Synthesis and antiallergy activity of [1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyrimidin-9(3H)-one derivatives. II. 6-Alkyl- and 6-cycloalkylalkyl derivatives
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A series of 6-alkyl- or 6-(cycloalkylalkyl)-[1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]pyr imidin-9(3H)-ones 1b-o was synthesized from the corresponding 1,3,4-thiadiazol-5-amines 3b-o and the antiallergic activities of the products were evaluated. Among the compounds 6-(2-cyclohexylethyl)-[1,3,4]thiadiazolo[3,2-a]-1,2,3-triazolo[4,5-d]p yrimidin-9(3H)-one 1h, whose X-ray crystallographic stereostructure is shown, was found to be a promising new antiallergic agent, which has low toxicity and dual activity as a leukotriene D4 receptor antagonist and as an orally active mast cell stabilizer.
- Yokohama,Miwa,Aibara,Fujiwara,Matsumoto,Nakayama,Iwamoto,Mori,Moroi,Tsukada,Isoda
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p. 2391 - 2398
(2007/10/02)
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- 2-PYRROLIDONE SUBSTITUTED DIHYDROXY ALKANOIC, ALKENOIC AND ALKYNOIC ACIDS, COMPOSITIONS AND HMG-COA REDUCTASE INHIBITION THEREWITH
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Antihypercholesterolemic activity has been discovered in compounds of the formula and pharmaceutically acceptable salts thereof, wherein: Z is X is lower alkyl, lower alkenyl, or lower alkenyl; R1 is hydrogen, alkyl, alkenyl, aryl, alkylaryl, or substituted aryl having one or more substituents; and one of R2 and R3 is hydrogen and the other is hydrogen, alkyl, alkenyl, aryl, alkylaryl or alkenyl aryl; or R2 and R3 are both lower alkyl; or R2 and R3 together complete a substituted or unsubstituted hydrocarbon ring that is cycloalkyl or cycloalkenyl with substituents as defined in the specification.
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- Modified Wittig Reactions Using Triethylamine and Lithium Halides: Synthesis of α,β-Unsaturated Esters from Ketones and Ethyl Bis(trifluoroethyl)phosphonoacetate
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A modified HWE reaction using triethylamine and lithium bromide with ethyl bis(trifluoroethyl)phosphonoacetate gives satisfactory yields of α,β-unsaturated esters from a variety of ketones.
- Rathke, Michael W.,Bouhlel, Ezzeddine
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p. 869 - 875
(2007/10/02)
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- A novel olefination of diazo-compounds with carbonyl compounds mediated by tributylstibine and catalytic amount of Cu(I)I
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A one-pot reaction of tributylstibine, diazo-compounds including dimethyl diazomalonate, ethyl diazoacetate and diazoacetylacetone, carbonyl compounds and catalytic amount of Cu(I)I resulted in olefination in high yields.
- Liao,Huang
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p. 5897 - 5900
(2007/10/02)
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- Studies of the use of elemento-organic compounds of the fifteenth and sixteenth groups in organic synthesis LXXI. Reaction of α-halogeno carboxylic derivatives with carbonyl compounds promoted by tributylstibine
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α,β-Unsaturated esters and amides were conveniently obtained from the trialkylstibine-promoted reaction of α-halogenocarboxylic derivatives with carbonyl compounds.In this reaction, a quaternary stibonium salt is an active intermediate that can be trapped and can undergo further reaction with the substrate.
- Huang, Yao-Zeng,Chen, Chen,Shen, Yanchang
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- A NOVEL OLEFINATION OF CARBONYL COMPOUNDS WITH α-BROMOACETIC ESTER MEDIATED BY TRI-n-BUTYLSTIBINE
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Tri-n-butylstibine has been found to mediate the olefination of carbonyl compounds by α-bromoacetic ester to give corresponding olefins in good yields.
- Huang, Yaozeng,Shen, Yanchang,Chen, Chen
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p. 2903 - 2904
(2007/10/02)
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- The Horner-Wadsworth-Emmons Modification of the Wittig Reaction Using Triethylamine and Lithium or Magnesium Salts
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A variety of aldehydes were converted into the corresponding α,β-unsaturated esters using triethyl phosphonoacetate and triethylamine in the presence of lithium or magnesium halides.Under the same conditions, simple methyl ketones were unreactive.
- Rathke, Michael W.,Nowak, Michael
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p. 2624 - 2626
(2007/10/02)
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- A NEW EFFICIENT DECARBOXYLATIVE REDUCTION OF γ-CARBAMOYLOXY-α,β-UNSATURATED ESTERS WITH LITHIUM DIALKYLCUPRATE
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A new synthetically useful decarboxylative reduction of γ-carbamoyloxy-α,β-unsaturated esters with lithium dialkylcuprate under mild condition was described.
- Ibuka, Toshiro,Chu, G.-Namg,Yoneda, Fumio
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p. 3247 - 3250
(2007/10/02)
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- A New Synthesis of α,β-Unsaturated Carboxylic Esters Using Dialkyltelluronium Carbethoxymethylide
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Dialkyltelluronium carbethoxymethylide was found to condense with a variety of carbonyl compounds to yield α,β-unsaturated carboxylic esters in good yields.
- Osuka, Atsuhiro,Mori, Yasuo,Shimizu, Hirohito,Suzuki, Hitomi
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p. 2599 - 2602
(2007/10/02)
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- Cyclopentane derivatives useful as perfuming agents
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Cyclopentane derivatives useful as odor-modifying ingredients for manufacturing perfumes and perfumed products and perfume compositions containing same.
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