- Chemoenzymatic synthesis of (3R,4S)- and (3S,4R)-3-methoxy-4-methylaminopyrrolidine
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An efficient and a convenient enantioselective synthesis of (3R,4S)-3-methoxy-4-methylaminopyrrolidine has been carried out by a lipase-mediated resolution protocol. This method describes the preparation of (±)-1-Cbz-cis-3-azido-4-hydroxypyrrolidine start
- Kamal, Ahmed,Shaik, Ahmad Ali,Sandbhor, Mahendra,Malik, M. Shaheer,Azeeza, Shaik
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- Tandem ring-closing metathesis/transfer hydrogenation: Practical chemoselective hydrogenation of alkenes
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An operationally simple chemoselective transfer hydrogenation of alkenes using ruthenium metathesis catalysts is presented. Of great practicality, the transfer hydrogenation reagents can be added directly to a metathesis reaction and effect hydrogenation of the product alkene in a single pot at ambient temperature without the need to seal the vessel to prevent hydrogen gas escape. The reduction is applicable to a range of alkenes and can be performed in the presence of aryl halides and benzyl groups, a notable weakness of Pd-catalyzed hydrogenations. Scope and mechanistic considerations are presented.
- Connolly, Timothy,Wang, Zhongyu,Walker, Michael A.,McDonald, Ivar M.,Peese, Kevin M.
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supporting information
p. 4444 - 4447
(2015/01/09)
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- Total syntheses of (-)-hanishin, (-)-longmide B, and (-)-longmide B methyl ester via a novel preparation of N-substituted pyrrole-2-carboxylates
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A novel preparation of N-substituted pyrrole-2-carboxylates has been developed based upon 1,3-dipolar cycloaddition and a conventional hydrogenolysis. By using this method as the key step, total syntheses of natural alkaloids (-)-hanishin, (-)-longmide B,
- Cheng, Guolin,Wang, Xinyan,Bao, Hailin,Cheng, Chuanjie,Liu, Nan,Hu, Yuefei
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p. 1062 - 1065
(2012/04/23)
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- 3-HYDROXYPYRROLIDINE INHIBITORS OF 5?-METHYLTHIOADENOSINE PHOSPHORYLASE AND NUCLEOSIDASE
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The present invention relates to 3-hydroxypyrrolidine compounds of the general formula (I) which are inhibitors of 5?-methylthioadenosine phosphorylase or 5?-methylthioadenosine nucleosidase. The invention also relates to the use of these compounds in the treatment of diseases or conditions in which it is desirable to inhibit 5?-methylthioadenosine phosphorylase or 5?-methylthioadenosine nucleosidase including cancer, and to pharmaceutical compositions containing the compounds
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Page/Page column 35-36
(2011/02/24)
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- Design and synthesis of potent "sulfur-free" transition state analogue inhibitors of 5′-methylthioadenosine nucleosidase and 5′-methylthioadenosine phosphorylase
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5′-Methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) is a dual substrate bacterial enzyme involved in S-adenosylmethionine (SAM) related quorum sensing pathways that regulates virulence in many bacterial species. MTANs from many bacteria are directly involved in the quorum sensing mechanism by regulating the synthesis of autoinducer molecules that are used by bacterial communities to communicate. In humans, 5′-methylthioadenosine phosphorylase (MTAP) is involved in polyamine biosynthesis as well as in purine and SAM salvage pathways and thus has been identified as an anticancer target. Previously we have described the synthesis and biological activity of several aza-C-nucleoside mimics with a sulfur atom at the 5′ position that are potent E. coli MTAN and human MTAP inhibitors. Because of the possibility that the sulfur may affect bioavailability, we were interested in synthesizing "sulfur-free" analogues. Herein we describe the preparation of a series of "sulfur-free" transition state analogue inhibitors of E. coli MTAN and human MTAP that have low nano-to picomolar dissociation constants and are potentially novel bacterial anti-infective and anticancer drug candidates.
- Longshaw, Alistair I.,Adanitsch, Florian,Gutierrez, Jemy A.,Evans, Gary B.,Tyler, Peter C.,Schramm, Vern L.
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experimental part
p. 6730 - 6746
(2010/12/24)
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- DERIVATIVES OF OXABISPIDINE AS NEURONAL NICOTINIC ACETYLCHOLINE RECEPTOR LIGANDS
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The present invention relates to compounds of formula (I) that bind to and modulate the activity of neuronal nicotinic acetylcholine receptors, to processes for preparing these compounds, to pharmaceutical compositions containing these compounds, and to m
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Page/Page column 28-29
(2010/04/03)
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- 5-HYDROXYMETHYL-OXAZOLIDIN-2-ONE-DERIVATIVES AND THEIR USES AS ANTIBACTERIALS
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The invention relates to novel chimeric antibiotics of formula I wherein R1 represents OH, OPO3H2 or OCOR5; R2 represents H, OH or OPO3H2; A represents N or CR6; Rsup
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Page/Page column 14
(2009/10/06)
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- 5-HYDROXYMETHYL-OXAZOLIDIN-2-ONE DERIVATIVES
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The invention relates to novel chimeric antibiotics of formula (I) wherein R1 represents OH, OPO3H2 or OCOR5; R2 represents H, OH or OPO3H2; A represents N or CR6; Rs
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Page/Page column 33
(2008/12/05)
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- Development of a practical and scalable preparation using sonication of Pd/fibroin catalyst for chemoselective hydrogenation
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A practical and efficient preparation method of palladium-fibroin (Pd/Fib), silk-fibroin-supported Pd(0) by means of sonication, has been developed. The Pd/Fib catalyst could be prepared within 12 h at room temperature starting from commercial silk-fibroin and Pd(OAc)2 in MeOH, whereas our previous preparation method required at least 4 days. The present improved process is applicable to a large-scale preparation of Pd/Fib. The Pd/Fib prepared by the present method also catalyzed chemoselective hydrogenation of acetylenes, olefins, and azides in the presence of aromatic ketones, aldehydes, and halides; N-Cbz protective groups; and benzyl esters, which are readily hydrogenated under the Pd/C- or Pd/C(en)-catalyzed hydrogenation conditions. Copyright Taylor & Francis Group, LLC.
- Kitamura, Yoshiaki,Tanaka, Asami,Sato, Mutsumi,Oono, Keiji,Ikawa, Takashi,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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p. 4381 - 4388
(2008/03/13)
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- Synthesis of the 3-(3,4,5-trimethoxyphenyl)-pyrrolidine: A new conformationally constrained mescaline analogue
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The total synthesis of the 3-(3,4,5-trimethoxyphenyl)-pyrrolidine, a new and conformationally constrained mescaline analogue, was accomplished in a concise and efficient manner. The synthetic route encompassed only 4 steps from the starting N-Cbz-3-pyrrol
- Barreto, Ricardo De L.,Nascimbem, Laura B. L. R.,Correia, Carlos Roque Duarte
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p. 2011 - 2018
(2008/02/05)
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- Pd/C-catalyzed chemoselective hydrogenation in the presence of diphenylsulfide
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A Pd/C-catalyzed chemoselective hydrogenation using diphenylsulfide as a catalyst poison has been developed. This methodology selectively hydrogenates olefin and acetylene functionalities without hydrogenolysis of aromatic carbonyls and halogens, benzyl esters, and N-Cbz protective groups.
- Mori, Akinori,Miyakawa, Yumi,Ohashi, Eri,Haga, Tomoko,Maegawa, Tomohiro,Sajiki, Hironao
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p. 3279 - 3281
(2007/10/03)
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- Chemoselective hydrogenation method catalyzed by Pd/C using diphenylsulfide as a reasonable catalyst poison
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While Pd/C is one of the most useful catalysts for hydrogenation, the high catalyst activity of Pd/C causes difficulty in its application to chemoselective hydrogenation between different types of reducible functionalities. In order to achieve chemoselective hydrogenation using Pd/C, we investigated catalyst poison as a controller of the catalyst activity. We found that the addition of Ph2S (diphenylsulfide) to the Pd/C-catalyzed hydrogenation reaction mixture led to reasonable deactivation of Pd/C. By the use of the Pd/C-Ph2S catalytic system, olefins, acetylenes, and azides can be selectively reduced in the coexistence of aromatic carbonyls, aromatic halides, cyano groups, benzyl esters, and N-Cbz (benzyloxycarbonyl) protecting groups. The present method is promising as a general and practical chemoselective hydrogenation process in synthetic organic chemistry.
- Mori, Akinori,Mizusaki, Tomoteru,Miyakawa, Yumi,Ohashi, Eri,Haga, Tomoko,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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p. 11925 - 11932
(2007/10/03)
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- Highly chemoselective hydrogenation method using novel finely dispersed palladium catalyst on silk-fibroin: Its preparation and activity
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A palladium-fibroin complex (Pd/Fib) was prepared by soaking silk-fibroin in MeOH solution of Pd(OAc)2 for 2 days (under Ar atmosphere) - 4 days (under air). Pd(OAc)2 was gradually absorbed by fibroin and the rapid reduction of fibroin conjugated Pd(OAc)2 proceeded with MeOH as a reductant at room temperature to be the Pd(0) complex. Pd/Fib catalyzed chemoselective hydrogenation of acetylenes, olefins and azides in the presence of aromatic ketones and aldehydes, halides, N-Cbz protective groups and benzyl esters which are readily hydrogenated using Pd/C or Pd/C(en) as a catalyst.
- Ikawa, Takashi,Sajiki, Hironao,Hirota, Kosaku
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p. 2217 - 2231
(2007/10/03)
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- Deallyloxy- and debenzyloxycarbonylation of protected alcohols, amines and thiols via a naphthalene-catalysed lithiation reaction
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The naphthalene-catalysed lithiation of Alloc- and Cbz-protected alcohols, amines and thiols in THF at 0°C led, after quenching with methanol, to the recovery of the free alcohols, amines and thiols in short reaction times and with very good yields. The selectivity for the removal of the Alloc- or the Cbz- group in a polyfunctionalised substrate has been studied. The selective reductive cleavage of a benzylic carbon-oxygen bond was achieved in the presence of an allylic carbon-oxygen or carbon-nitrogen bond. This method represents a great improvement in comparison with the previously reported deprotection procedures by dissolving metals, since it avoids the use of the toxic liquid ammonia and, therefore, the need to perform the reaction at low temperatures.
- Behloul, Cherif,Guijarro, David,Yus, Miguel
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p. 9319 - 9324
(2007/10/03)
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- Chemoenzymatic synthesis of (3S,4S)- and (3R,4R)-3-methoxy-4- methylaminopyrrolidine
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Facile chemoenzymatic enantioselective synthesis of (3S,4S)-3-methoxy-4- methylaminopyrrolidine, a key intermediate for a new quinolone antitumor compound AG-7352 has been described. This methodology illustrates the preparation of 3-azido-1-benzyloxycarbo
- Kamal, Ahmed,Shaik, Ahmad Ali,Sandbhor, Mahendra,Malik, M. Shaheer,Kaga, Harumi
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p. 8057 - 8059
(2007/10/03)
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- Pd/C(en)-catalyzed chemoselective hydrogenation with retention of the N-Cbz protective group and its scope and limitations
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A chemoselective method for the hydrogenation of acetylene, olefin, azide, nitro and benzyl ester functionalities with retention of the aliphatic N-Cbz group was established. The chemoselectivity was accomplished by using a combination of 5% Pd/C-ethylenediamine [5% Pd/C(en)] and THF (or 1,4-dioxane) as a solvent, and the scope and limitations of this methodology were investigated. These results reinforce the utility of N-Cbz protective groups in synthetic chemistry, especially in peptide synthesis. (C) 2000 Elsevier Science Ltd.
- Hattori, Kazuyuki,Sajiki, Hironao,Hirota, Kosaku
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p. 8433 - 8441
(2007/10/03)
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- A formal synthesis of (+)-α-allokainic acid via sulfanyl radical addition-cyclization reaction
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Sulfanyl radical addition-cyclization of the diallylamines in the presence of thiophenol and AIBN gave the 2,3,4-trisubstituted pyrrolidines which were effectively converted into the known key intermediate for the synthesis of (+)-α-allokainic acid via conversion of the phenylsulfanylmethyl group into the isopropenyl group at the 4-position.
- Miyata, Okiko,Ozawa, Yoshiki,Ninomiya, Ichiya,Aoe, Keiichi,Hiramatsu, Hajime,Naito, Takeaki
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p. 321 - 333
(2007/10/03)
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