- Asymmetric aldol reaction of thiazole-carbaldehydes: Regio- And stereoselective synthesis of tubuvalin analogues
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The first organocatalytic enantioselective approach to precursors of tubuvaline (pre-Tuv) is presented employing a prolinamide-catalyzed aldol reaction of easily accessible thiazole-carbaldehyde with methyl isopropyl ketone "on water" in excellent yield as well as regio- and enantioselectivities. The analogues of pre-Tuv were achieved using an l-proline-catalyzed direct asymmetric aldol reaction of substituted thiazole-carbaldehydes with acetone. A direct and flexible approach to the tubavaline (Tuv) core of tubusylins has been established employing the reductive amination of the pre-Tuv species. The key aldol reaction should greatly expand the potential of this strategy to the synthesis of natural product tubulysins and a range of analogues.
- Paladhi, Sushovan,Das, Joydeb,Samanta, Mousumi,Dash, Jyotirmayee
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- Design, synthesis, and antitumor activity evaluation of pretubulysin analogs
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Pretubulysin, a biosynthetic precursor of the tubulysins, shows potent biological activity in a variety of tumor cell lines. Although there are several total synthesis routes to tubulysin and pretubulysin reported, the commercialization still has been hampered due to the complexity of the structure. To find structurally simpler pretubulysin analogs, a series of 2-(3-(methylamino)propyl)thiazole-4-carboxamides are designed and synthesized, and their anticancer activities are screened using MCF-7 (breast cancer), and NCI-H157 (lung cancer) cell lines. Taxol (IC50?=?0.01?μM) and pretubulysin are used as the control. Compounds 8c (IC50?=?0.05?μM, MCF-7; 0.09?μM, NCI-H157) and 8h (IC50?=?0.01?μM, MCF-7; 0.02?μM, NCI-H157) exhibited certain antitumor activities comparable to those of Taxol. The urea analogs of pretubulysin might represent a promising scaffold for the further development of novel antitumor drugs.
- Xu, Xiangrong,Fan, Meixia,Qi, Junhui,Yao, Lei
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p. 341 - 351
(2021/06/14)
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- New BI and TRI-Thiazole copper (II) complexes in the search of new cytotoxic drugs against breast cancer cells
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New thiazolyl derivatives (BT and TT) and their copper (II) complexes [Cu2Cl2(BT)2] (Cu-BT) and [Cu4ClO2(TT)2]PF6?3.5H2O (Cu-TT) were synthesized and characterized by elemental analysis, 1H NMR and 13C NMR, HRMS, X-ray diffraction, IR and UV–Vis spectroscopies. The crystal structure of Cu-BT shows the formation of a dinuclear complex where each copper(II) center is bonded to two thiazol N atoms, from different BT ligands, one deprotonated amide N atom, an O atom from the ester terminal groups and a chlorine atom. The structure found for Cu-TT is a positively charged tetranuclear moiety containing two deprotonated TT ligands, a chlorine anion, two hydroxide anions acting as bridges between the copper centers and a water molecule. The cytotoxic activity of both copper complexes was evaluated on metastatic breast cancer cell lines, characterized for its rapidly dividing behavior. Both, Cu-BT and Cu-TT, show higher cytotoxic activity against these tumor cells than free BT and TT and also than cisplatin. In addition, we found that both complexes interact with DNA. Consistently, they also show cytotoxicity against a rapidly dividing non-tumor cell line, although with higher IC50, being such interaction and selectivity an indicator of the possible coexistence of more than one mechanism of action.
- Alvarez, Natalia,Velluti, Francesca,Guidali, Florencia,Serra, Gloria,Gabriela Kramer,Ellena, Javier,Facchin, Gianella,Scarone, Laura,Torre, María H.
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- Synthesis and biological evaluation of 2,4,5-trisubstituted thiazoles as antituberculosis agents effective against drug-resistant tuberculosis
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The dormant and resistant form of Mycobacterium tuberculosis presents a challenge in developing new anti-tubercular drugs. Herein, we report the synthesis and evaluation of trisubstituted thiazoles as antituberculosis agents. The SAR study has identified a requirement of hydrophobic substituent at C2, ester functionality at C4, and various groups with hydrogen bond acceptor character at C5 of thiazole scaffold. This has led to the identification of 13h and 13p as lead compounds. These compounds inhibited the dormant Mycobacterium tuberculosis H37Ra strain and M. tuberculosis H37Rv selectively. Importantly, 13h and 13p were non-toxic to CHO cells. The 13p showed activity against multidrug-resistant tuberculosis isolates.
- Karale, Uttam B.,Krishna, Vagolu Siva,Krishna, E. Vamshi,Choudhari, Amit S.,Shukla, Manjulika,Gaikwad, Vikas R.,Mahizhaveni,Chopra, Sidharth,Misra, Sunil,Sarkar, Dhiman,Sriram, Dharmarajan,Dusthackeer, V.N. Azger,Rode, Haridas B.
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p. 315 - 328
(2019/06/14)
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- Development of a practical and scalable route for the preparation of the deacetoxytubuvaline (dTuv) fragment of pretubulysin and analogs
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We present herein a novel and convenient route for the scaling-up of the dTuv fragment of pretubulysin. The newly conceived chemical path involves a practical and efficient one-step procedure for the preparation of a key thiazole intermediate, followed by high-yielding Wittig olefination/reduction steps. The optimized route, starting from the inexpensive and non-toxic l-cysteine, encompasses five synthetic steps and only two chromatographic purifications, thus displaying a dramatically increased overall yield. The versatility of the proposed approach also provides new hints for the exploration of pretubulysin derivatives bearing diverse heterocyclic portions.
- Brindisi, Margherita,Maramai, Samuele,Grillo, Alessandro,Brogi, Simone,Butini, Stefania,Novellino, Ettore,Campiani, Giuseppe,Gemma, Sandra
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supporting information
p. 920 - 923
(2016/02/05)
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- Solvent-free synthesis of bacillamide analogues as novel cytotoxic and anti-inflammatory agents
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Synthesis of fourteen analogues of bacillamide, a bioactive tryptamide alkaloid of marine origin, has been accomplished through a highly efficient convergent route. The present solvent-free protocol involves the formation of thiazole ring in the initial step followed by amide coupling between substituted ethyl 2-alkyl/aryl/heteroaryl/amino/aminoarylthiazole-4-carboxylates and tryptamine in presence of 2-hydroxy-4,6-dimethylpyrimidine, a solid phase catalyst to yield N-[2-(1H-indol-3-yl)ethyl]-2-alkyl/aryl/heteroaryl/amino/aminoarylthiazole-4-carboxamides as bacillamide analogues having structural variation at position-2 of thiazole ring. Bacillamide and its analogues were evaluated for their cytotoxic activity against three cancer cell lines (HCT-116, MDA-MD-231 and JURKAT cell lines) using colorimetric cell proliferation assay. Compounds 17a and 17b exhibited potent anti-cell proliferation activity with IC50values in the range of ～3.0?μM and ～0.1–0.6?μM, respectively against these cell lines. Preliminary mechanism of action studies indicates that these compounds initiate caspase dependent apoptosis. Also, compounds 16d, 16f, 17a and 17d exhibited excellent anti-inflammatory activity comparable to well-known NSAID indomethacin and better to bacillamide, when evaluated using carrageenan induced rat hind paw oedema method.
- Kumar, Sunil,Aggarwal, Ranjana,Kumar, Virender,Sadana, Rachna,Patel, Bhumi,Kaushik, Pawan,Kaushik, Dhirender
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p. 718 - 726
(2016/08/15)
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- Exploration and Optimization of an Efficient One-pot Sequential Synthesis of Di/tri-substituted Thiazoles from α-Bromoketones, Thioacids Salt, and Ammonium Acetate
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Exploration of scope of an optimized one-pot sequential procedure for preparing of 2,4-di- and 2,4,5-tri-substituted thiazoles has been accomplished. The synthesis was performed by the initial formation of a β-keto-thioester intermediate from nucleophilic substitution of α-bromoketones with thioacid potassium salts, followed by treatment with ammonium acetate and one equivalent of acetic acid in toluene to form imine intermediate eventually leading to cyclization yielding thiazoles. This procedure should be highlighted with a flexible way to control the substitution pattern around thiazole ring by choosing appropriately substituted α-bromoketones even containing acid labile functionality and thioacid potassium salts, and thus its applicability is very wide.
- Venkateswararao, Eeda,Jalani, Hitesh B.,Manoj,, Manickam,Jung, Sang-Hun
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supporting information
p. 1449 - 1456
(2016/09/24)
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- Synthesis of substituted esters of imidazoles, oxazoles, thiazoles, and diethyl pyrazine-2,5-dicarboxylate from a common acyclic precursor employing C-formylation strategy
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A novel synthetic route to substituted esters of imidazoles, oxazoles, thiazoles, and diethyl pyrazine-2,5-dicarboxylates via C-formylation of glycine ethyl ester hydrochloride is reported. This methodology is simple, robust, and gives good yields of different heterocyclic esters in one or two steps from a common acyclic precursor and is amenable to large scale synthesis.
- Khose, Goraksha,Shinde, Shailesh,Panmand, Anil,Kulkarni, Ravibhushan,Munot, Yogesh,Bandyopadhyay, Anish,Barawkar, Dinesh,Patil, Santoshkumar N.
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supporting information
p. 2671 - 2674
(2014/05/06)
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- An efficient total synthesis of (-)-epothilone B
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An efficient total synthesis of (-)-epothilone B has been achieved in ca. 8% yield over 11 steps from 9 (or 10 steps from 7/8), which features a bissiloxane-tethered ring closing metathesis reaction to approach the trisubstituted (Z) double bond and forms a new basis for further development of an industrial process for epothilone B and ixabepilone.
- Wang, Jie,Sun, Bing-Feng,Cui, Kai,Lin, Guo-Qiang
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supporting information
p. 6354 - 6357
(2013/02/23)
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- An efficient synthesis of 2,4′-bi-1,3-oxa(thia)zoles as scaffolds for bioactive products
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A rapid and efficient methodology to prepare 2,4′-bi-1,3-azoles as scaffolds for biologically active marine natural products is described. Hantzsch reaction and oxidative cyclodehydration of β-hydroxy amides or thioamides were used to construct the azole rings. The obtained biheterocycles displayed no cytotoxicity on HCT-15 cell line.
- Pena,Scarone,Manta,Serra
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experimental part
p. 703 - 709
(2012/02/01)
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- Oxidation of 4-carboxylate thiazolines to 4-carboxylate thiazoles by molecular oxygen
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A facile and environment-benign oxidation by molecular oxygen was applied for the conversion of 4-carboxylate thiazolines to 4-carboxylate thiazoles. The substituent effect on thiazoline ring was investigated. It was found that electron-poor group on the thiazoline ring could facilitate the oxidation.
- Huang, Yue,Gan, Haifeng,Li, Shang,Xu, Jinyi,Wu, Xiaoming,Yao, Hequan
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supporting information; experimental part
p. 1751 - 1753
(2010/05/18)
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- Method for Carrying Out Chemical Reactions with the Aid of an Inductively Heated Heating Medium
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The invention relates to a method for carrying out a chemical reaction for producing a target compound by heating in a reactor a reaction medium containing at least one first reactant, such that a chemical bond inside the first reactant or between the first and a second reactant is formed or modified. The reaction medium is brought into contact with a solid heating medium that can be warmed by electromagnetic induction and that is inside the reactor and is surrounded by the reaction medium. Said heating medium is heated by electromagnetic induction with the aid of an inductor and the target bond is formed from the first reactant or from the first and a second reactant and said target bond is separated from the heating medium.
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Page/Page column 11
(2010/10/19)
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- Design and synthesis C6-C8 bridged epothilone a
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A conformationally restrained epothilone A analogue (3) with a short bridge between methyl groups at C6 and C8 was designed and synthesized. Preliminary biological evaluation indicates 3 to be only weakly active (IC50 = 8.5 μM) against the A2780 human ovarian cancer cell line.
- Zhan, Weiqiang,Jiang, Yi,Brodie, Peggy J.,Kingston, David G. I.,Liotta, Dennis C.,Snyder, James P.
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supporting information; experimental part
p. 1565 - 1568
(2009/04/10)
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- Inductive heating for organic synthesis by using functionalized magnetic nanoparticles inside microreactors
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(Chemical Equation Presented) The heat is on! Ferromagnetic materials heated by induction in an electromagnetic field have found synthetic application. Best results were obtained when superparamagnetic nanoparticles coated with SiO2 were incorporated in a microfluidic reactor and transformations were performed under flow conditions. These magnetic particles can be doped with Pd and used as heated heterogeneous catalysts.
- Ceylan, Sascha,Friese, Carsten,Lammel, Christian,Mazac, Karel,Kirschning, Andreas
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supporting information; experimental part
p. 8950 - 8953
(2009/05/30)
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- Biaryloxymethylarenecarboxylic acids as glycogen synthase activators
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The present invention relates to compounds of formula (I) wherein Ar, Ar2, R2, R3, R4, m, p and s are as defined in the description and claims, and pharmaceutically acceptable salts thereof. The compounds are useful for the treatment and/or prophylaxis of diseases that are associated with the activation of the glycogen synthase enzyme, such as diabetes.
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Page/Page column 21
(2008/06/13)
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- HYDRAZONE DERIVATIVE
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A compound represented by the following formula (I): wherein R1 represents hydrogen, aryl which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc.; R2 represents hydrogen, aryl which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc.; R3 represents hydrogen, etc.; Ar represents a divalent group derived from aromatic hydrocarbon, etc.; X represents a single bond, linear or branched alkylene having from 1 to 3 carbon atoms which may have a substituent, etc.; and G represents halogen, a saturated or unsaturated 5- or 6-membered cyclic hydrocarbon group which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc., a salt thereof or a solvate thereof; and an agent for inhibiting aggregation and/or deposition of an amyloid protein or an amyloid-like protein, which comprises the compound, a salt thereof or a solvate thereof
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Page/Page column 47
(2010/11/08)
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- Design, synthesis and biological evaluation of novel, simplified analogues of laulimalide: Modification of the side chain
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Novel, simplified analogues of the microtubule-stabilizing anticancer agent laulimalide, including the first derivatives with unnatural side chains, were designed by molecular modelling, synthesized by a late-stage diversification strategy, and evaluated in vitro for growth inhibition of human ovarian carcinoma cell lines (A2780, A2780/AD10).
- Paterson, Ian,Menche, Dirk,Hakansson, Anders E.,Longstaff, Adrian,Wong, David,Barasoain, Isabel,Buey, Ruben M.,Diaz, J. Fernando
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p. 2243 - 2247
(2007/10/03)
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- Total syntheses of epothilones B and D
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A convergent, total synthesis of epothilones B (2) and D (4) is described. The key steps are Normant coupling to establish the desired (Z)-stereochemistry at C12-C13, Wadsworth-Emmons olefination of methyl ketone 28 with the phosphonate ester 8, diastereoselective aldol condensation of aldehyde 5 with the enolate of keto acid derivatives to form the C6-C7 bond, selective deprotection of acid 52, and macrolactonization.
- Jung, Jae-Chul,Kache, Rajashaker,Vines, Kimberly K.,Zheng, Yan-Song,Bijoy, Panicker,Valluri, Muralikrishna,Avery, Mitchell A.
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p. 9269 - 9284
(2007/10/03)
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- 4-[(4-(CARBOXYETHYL) PIPERIDINYL) METHYL] PYRROLIDINES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
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3-Substituted pyrrolidines having a 4-carboxypiperidinylmethyl substituent on the 4-position of the ring are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-3 and/or CCR-5.
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- 4(SPIROPIPERIDINYL)METHYL SUBSTITUTED PYRROLIDINES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
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3-Substituted pyrrolidines having a spiropiperidinylmethyl substituent on the 4-position of the ring are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-3 and/or CCR-5.
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- NOVEL BENSOPHENONE DERIVATIVES OR SALTS THEREOF
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A benzophenone derivative represented by the following formula: whereinR1 represents, for example, an optionally substituted heterocyclic group, or a substituted phenyl group; Z represents, for example, an alkylene group; R2 represents, for example, a carboxyl group optionally protected with alkyl;R3 represents, for example, an optionally protected hydroxyl group; R4 represents, for example, an optionally substituted cycloalkyloxy group; and R5 represents, for example, a hydrogen atom, ???or a salt thereof has anti-arthritic activity, inhibits bone destruction caused by arthritis, and provides high safety and excellent pharmacokinetics and thus is useful as therapeutic agent for arthritis. These compounds have inhibitory effect on AP-1 activity and are useful as preventive or therapeutic agent for diseases in which excessive expression of AP-1 is involved.
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- Non-covalent thrombin inhibitors featuring P3-heterocycles with P1-monocyclic arginine surrogates
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Investigations on P2-P3-heterocyclic dipeptide surrogates directed towards identification of an orally bioavailable thrombin inhibitor led us to pursue novel classes of achiral, non-covalent P1-arginine derivatives. The design, synthesis, and biological activity of inhibitors NC1-NC30 that feature three classes of monocyclic P1-arginine surrogates will be disclosed: (1) (hetero)aromatic amidines, amines and hydroxyamidines, (2) 2-aminopyrazines, and (3) 2-aminopyrimidines and 2-aminotetrahydropyrimidines.
- Reiner, John E.,Siev, Daniel V.,Araldi, Gian-Luca,Cui, Jingrong Jean,Ho, Jonathan Z.,Reddy, Komandla Malla,Mamedova, Lala,Vu, Phong H.,Lee, Kuen-Shan S.,Minami, Nathaniel K.,Gibson, Tony S.,Anderson, Susanne M.,Bradbury, Annette E.,Nolan, Thomas G.,Semple, J. Edward
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p. 1203 - 1208
(2007/10/03)
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- Stereoselective syntheses of epothilones A and B via nitrile oxide cycloadditions and related studies
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The expedient and fully stereocontrolled synthesis of epothilones A and B are described. The routes described make extensive study of nitrile oxide cycloadditions as surrogates for aldol addition reactions and have led to the realization of a highly convergent synthesis based on the Kanemasa hydroxyl-directed nitrile oxide cycloaddition. As well, our synthetic efforts have led to the development of new reaction methodologies and served as the proving ground for several modern methods for asymmetric carbon-carbon bond formation.
- Bode,Carreira
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p. 6410 - 6424
(2007/10/03)
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- Asymmetric synthesis of 2-alkyl-3-thiazoline carboxylates: Stereochemistry of the MnO2-mediated oxidation of cis- and trans-2-alkyl-thiazolidine-(4R)-carboxylates
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The asymmetric synthesis of a series of 3-thiazoline carboxylates, 2, was effected by MnO2 oxidation of the corresponding cis/trans thiazolidines, 1. The stereochemistry of the oxidation reaction was studied using NMR and chiral GC analyses. Compounds 2 were obtained with enantiomeric excesses (e.e.s) in the range of 40-100%.
- Fernandez, Xavier,Duach, Elisabet
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p. 1279 - 1286
(2007/10/03)
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- Towards the synthesis of epothilone A: Enantioselective preparation of the thiazole side-chain and macrocyclic ring closure
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A synthetic approach to a new class of microtubule-stabilizing natural products is described which employs a macrocyclic olefination strategy to cyclize the 16-membered lactone ring. The C13-C19 thiazole subunit of epothilone A and B is prepared in high enantioselectivity using a catalytic asymmetric allylation reaction.
- Taylor, Richard E.,Haley, Jeffrey D.
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p. 2061 - 2064
(2007/10/03)
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- Studies of mild dehydrogenations in heterocyclic systems
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The use of bromotrichloromethane-DBU is described for the selective oxidative conversion of several dihydro-heterocyclic systems to the corresponding heteroaromatics. Oxidative dehydrogenations to afford 4-hydroxy-2-pyridinones are examined under a variety of conditions. Studies of phenylselenenylation and peracid oxidation provide the novel spirocyclic oxirane 10.
- Williams, David R.,Lowder, Patrick D.,Gu, Yu-Gui,Brooks, Dawn A.
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p. 331 - 334
(2007/10/03)
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- Synthesis of 2-substituted-4-carbethoxythiazoles
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In the presence of boron trifluoride etherate, aryl and alkylthioamides react with ethyl diazopyruvate to give high yields of corresponding thiazoles.
- Kim, Hong-Seok,Kwon, Il-Cheon,Kim, Oh-Hwoan
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p. 937 - 940
(2007/10/03)
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