- Engineering a homochiral metal-organic framework based on an amino acid for enantioselective separation
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A chiral metal-organic framework possessing an open amphiphilic channel is constructed from a dicarboxylate ligand derived from an amino acid and is shown to be an efficient and recyclable chiral solid adsorbent, which is capable of separating racemic secondary alcohols, epoxides, and ibuprofen with very high enantioselectivity.
- Tang, Haitong,Yang, Keke,Wang, Kun-Yu,Meng, Qi,Wu, Fan,Fang, Yu,Wu, Xiang,Li, Yougui,Zhang, WenCheng,Luo, Yunfei,Zhu, Chengfeng,Zhou, Hong-Cai
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p. 9016 - 9019
(2020/08/17)
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- Modulators of cell adhesion, methods and compositions therefor
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Compounds with activity as modulators of cell adhesion are disclosed. The compounds are derivatives of piperidin-4-amine. In some embodiments, a compound can be linked to a targeting agent, a pharmaceutically active substance and/or a support material. Methods for enhancing or inhibiting classical cadherin-mediated functions are also disclosed. The compounds can be used for the treatment or prevention of a variety of diseases including cancer. Compositions and devices, including skin patches comprising a compound are also disclosed. In addition, methods of synthesis of the compounds are provided.
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Paragraph 0220; 0221
(2019/04/18)
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- Chiral Bifunctional Metalloporphyrin Catalysts for Kinetic Resolution of Epoxides with Carbon Dioxide
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Chiral binaphthyl-strapped Zn(II) porphyrins with triazolium halide units were synthesized as bifunctional catalysts for kinetic resolution of epoxides with CO2. Several catalysts were screened by changing the linker length and nucleophilic counteranions, and the optimized catalyst accelerated the enantioselective reaction at ambient temperature to produce optically active cyclic carbonates and epoxides.
- Maeda, Chihiro,Mitsuzane, Mayato,Ema, Tadashi
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supporting information
p. 1853 - 1856
(2019/03/11)
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- Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
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New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
- Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
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supporting information
p. 3990 - 4001
(2017/11/22)
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- Chiral Macrocyclic Organocatalysts for Kinetic Resolution of Disubstituted Epoxides with Carbon Dioxide
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Among chiral macrocycles 1 synthesized, 1m with the 3,5-bis(trifluoromethyl)phenylethynyl group was the best organocatalyst for the enantioselective synthesis of cyclic carbonates from disubstituted or monosubstituted epoxides and CO2. The X-ray crystal structure of 1m revealed a well-defined chiral cavity with multiple hydrogen-bonding sites that is suitable for the enantioselective activation of epoxides. A catalytic cycle proposed was supported by DFT calculations.
- Ema, Tadashi,Yokoyama, Maki,Watanabe, Sagiri,Sasaki, Sota,Ota, Hiromi,Takaishi, Kazuto
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supporting information
p. 4070 - 4073
(2017/08/15)
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- Synthesis, radiolabeling and in vivo evaluation of [11C](R)-1- [4-[2-(4-methoxyphenyl)phenyl]piperazin-1-yl]-3-(2-pyrazinyloxy)-2-propanol, a potential PET radioligand for the 5-HT7receptor
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In the search for a novel serotonin 7 (5-HT7) receptor PET radioligand we synthesized and evaluated a new series of biphenylpiperazine derivatives in vitro. Among the studied compounds, (R)-1-[4-[2-(4-methoxyphenyl) phenyl]piperazin-1-yl]-3-(2-pyrazinyloxy)-2-propanol ((R)-16), showed the best combination of affinity, selectivity, and lipophilicity, and was thus chosen for carbon-11 labelling and evaluation in pigs. After intravenous injection, [11C](R)-16 entered the pig brain and displayed reversible tracer kinetics. Pretreatment with the 5-HT7receptor selective antagonist SB-269970 (1) resulted in limited decrease in the binding of [11C](R)-16, suggesting that this radioligand is not optimal for imaging the brain 5-HT7receptor in vivo but it may serve as a lead compound for the design of novel 5-HT7receptor PET radioligands.
- Hansen, Hanne D.,Lacivita, Enza,Di Pilato, Pantaleo,Herth, Matthias M.,Lehel, Szabolcs,Ettrup, Anders,Andersen, Valdemar L.,Dyssegaard, Agnete,De Giorgio, Paola,Perrone, Roberto,Berardi, Francesco,Colabufo, Nicola Antonio,Niso, Mauro,Knudsen, Gitte M.,Leopoldo, Marcello
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p. 152 - 163
(2014/05/06)
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- Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(iii)-salen complexes: A practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: Computational rationale for enantioselectivity
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A series of chiral polymeric Co(iii)-salen complexes based on a number of achiral and chiral linkers were synthesized and their catalytic performances were assessed in the asymmetric hydrolytic kinetic resolution of terminal epoxides. The effects of the linker were judiciously studied and it was found that in the case of the chiral BINOL-based polymeric salen complex 1, there was an enrichment in catalyst reactivity and enantioselectivity of the unreacted epoxide, particularly in the case of short as well as long chain aliphatic epoxides. Good isolated yields of the unreacted epoxide (up to 46% compared to 50% theoretical yield) along with high enantioselectivity (up to 99%) were obtained in most cases using catalyst 1. Further studies showed that catalyst 1 could retain its catalytic activity for six cycles under the present reaction conditions without any significant loss in activity or enantioselectivity. To show the practical applicability of the above synthesized catalyst we have synthesised some potent chiral β-blockers in moderate yield and high enantioselectivity using complex 1. The DFT (M06-L/6-31+G??//ONIOM(B3LYP/6-31G?:STO-3G)) calculations revealed that the chiral BINOL linker influences the enantioselectivity achieved with Co(iii)-salen complexes. Further, the transition state calculations show that the R-BINOL linker with the (S,S)-Co(iii)-salen complex is energetically preferred over the corresponding S-BINOL linker with the (S,S)-Co(iii)-salen complex for the HKR of 1,2-epoxyhexane. The role of non-covalent C-H?π interactions and steric effects has been discussed to control the HKR reaction of 1,2-epoxyhexane.
- Roy, Tamal,Barik, Sunirmal,Kumar, Manish,Kureshy, Rukhsana I.,Ganguly, Bishwajit,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
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p. 3899 - 3908
(2015/02/19)
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- Enantioselective α-hydroxylation of β-keto esters catalyzed by chiral S-timolol derivatives
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A screen of aryloxy aminopropanol organocatalysts derived from the β-blocker inhibitor S-timolol determined the most active catalyst of asymmetric α-hydroxylation of β-keto esters. (R)-1-(tert-butylamino)- 3-(3,4,5-trimethoxyphenoxy) propan-2-ol (3k) was the most effective derivative, enantioselectively catalyzing α-hydroxylation of β-keto esters using tert-butyl hydroperoxide as the oxidant in hexane to afford the corresponding products in excellent yield and with good enantioselectivity (up to 96% yield, 88% ee).
- Cai, Yuanchun,Lian, Mingming,Li, Zhi,Meng, Qingwei
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experimental part
p. 7973 - 7977
(2012/09/21)
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- Chiral nanoporous metal-metallosalen frameworks for hydrolytic kinetic resolution of epoxides
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Chiral nanoporous metal-organic frameworks are constructed by using dicarboxyl-functionalized chiral Ni(salen) and Co(salen) ligands. The Co(salen)-based framework is shown to be an efficient and recyclable heterogeneous catalyst for hydrolytic kinetic resolution (HKR) of racemic epoxides with up to 99.5% ee. The MOF structure brings Co(salen) units into a highly dense arrangement and close proximity that enhances bimetallic cooperative interactions, leading to improved catalytic activity and enantioselectivity in HKR compared with its homogeneous analogues, especially at low catalyst/substrate ratios.
- Zhu, Chengfeng,Yuan, Guozan,Chen, Xu,Yang, Zhiwei,Cui, Yong
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supporting information; experimental part
p. 8058 - 8061
(2012/07/14)
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- Directed evolution of an enantioselective epoxide hydrolase: Uncovering the source of enantioselectivity at each evolutionary stage
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Directed evolution of enzymes as enantioselective catalysts in organic chemistry is an alternative to traditional asymmetric catalysis using chiral transition-metal complexes or organocatalysts, the different approaches often being complementary. Moreover, directed evolution studies allow us to learn more about how enzymes perform mechanistically. The present study concerns a previously evolved highly enantioselective mutant of the epoxide hydrolase from Aspergillus niger in the hydrolytic kinetic resolution of racemic glycidyl phenyl ether. Kinetic data, molecular dynamics calculations, molecular modeling, inhibition experiments, and X-raystructural work for the wild-type (WT) enzyme and the best mutant revea l the basis of the large increase in enantioselectivity (E = 4.6 versus E = 115). The overall structures of the WT and the mutant are essentially identical, but dramatic differences are observed in the active site asrevealed by the X-ray structures. All of the experimental and computati onal results support a model in which productive positioning of the preferred (S)-glycidyl phenyl ether, but not the (R)-enantiomer, forms the basis of enhanced enantioselectivity. Predictions regarding substrate scope and enantioselectivity of the best mutant are shown to be possible.
- Reetz, Manfred T.,Bocola, Marco,Wang, Li-Wen,Sanchis, Joaquin,Cronin, Annette,et al.
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supporting information; experimental part
p. 7334 - 7343
(2009/10/17)
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- Enantioselective incorporation of carbon dioxide into epoxides catalyzed by optically active cobalt(II) complexes
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The enantioselective chemical fixation of CO2 into an epoxide was developed using an optically active ketoimi-natocobalt(II) complex as a chiral Lewis acid. In the presence of a catalytic amount of the cobalt complex and amine base, enantioselective CO2 fixation with an epoxide proceeded with kinetic resolution to afford the corresponding carbonate along with unreacted epoxide, both of which were optically active. To improve their enantioselectivities, the ligand structures of the cobalt complexes and amine bases were examined. Thus, the optimized catalytic system was successfully applied to various epoxides to obtain the corresponding optically active cyclic carbonates and to recover epoxides with good-to-high enantioselectivities.
- Yamada, Wataru,Kitaichi, Yasunori,Tanaka, Hirotaka,Kojima, Tomohide,Sato, Mitsuo,Ikeno, Taketo,Yamada, Tohru
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experimental part
p. 1391 - 1401
(2009/06/20)
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- Sequential Ru-Pd catalysis: A two-catalyst one-pot protocol for the synthesis of N- and O-heterocycles
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An atom economic, selective, and highly practical two-metal one-pot synthesis of heterocycles has been developed that efficiently affords enantio- and diastereopure N- and O-heterocyclic products. Furthermore, use of a chiral catalyst in the two-metal procedure allows formation of all possible diastereomers, even those that are traditionally difficult to access via cyclization routes due to thermodynamics. Interestingly, the nature of the enantiodiscriminating event differs between the use of amine versus alcohol nucleophiles. The method also affords heterocyclic products that are synthetically useful intermediates. Through the Z-vinylsilane a variety of stereodefined trisubstituted olefin products can be accessed including several all-carbon motifs. Finally, the utility of these heterocyclic products in total synthesis is demonstrated through concise syntheses of a kainoid intermediate, a constituent of oil of rose, and the ring B portion of bryostatin, a potent chemotherapeutic.
- Trost, Barry M.,Machacek, Michelle R.,Faulk, Brian D.
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p. 6745 - 6754
(2007/10/03)
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- A facile and convenient chemoenzymatic synthesis of optically active O-(4-methoxyphenyl)-glycidol and 1,2-diacyl-sn-glycerol
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A convenient preparation of the (R)- and (S)-enantiomers of O-(4-methoxyphenyl)-glycidol by a one-pot reduction of ketone 3 and in situ lipase mediated resolution is described. Activated moist aluminium oxide in the presence of Pseudomonas cepacia lipase immobilized on ceramic particles (PS-C) has been found effective for the transesterification leading to a high degree of enantioselectivity. These chiral glycidols were further used as a chiral precursor for the synthesis of biologically important 1,2-O-diacyl-sn-glycerol under mild reaction conditions. The present method is facile for the synthesis of chiral glycidols in high enantioselectivity when compared to the previously reported methods.
- Kamal, Ahmed,Sandbhor, Mahendra,Shaik, Ahmad Ali,Malik, M. Shaheer
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p. 1855 - 1859
(2007/10/03)
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- PROCESS FOR PRODUCING GLYCIDYL ETHER
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A process for producing a glycidyl ether and an optically active compound thereof with high yield and an optically high purity comprising reacting an alcohol with epihalohydrin in a base to thereby produce a glycidyl ether, the reaction performed in a two-layer system of a nonaqueous organic solvent and an aqueous solvent.
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- SUBSTITUTED HETEROCYCLIC COMPOUNDS USEFUL IN THE TREATMENT OF CARDIOVASCULAR DISEASES
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wherein: a.o. T is oxygen, sulfur, or NR11 , in which R11 is hydrogen or lower alkyl; V is -N1 is hydrogen, optionally substituted lower alkyl, optionally substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl; X2 is optionally substituted aryl or optionally substituted heteroaryl; Y is optionally substituted dihydroheteroarcyl; and Z1 and Z2 are independently optionally substituted alkylene of 1-4 carbon atoms, useful for the treatment of various disease states, in particular cardiovascular diseases such as atrial and ventricular arrhythmias, intermittent claudication, Prinzmetal’s (variant) angina, stable and unstable angina, exercise induced angina, congestive heart disease, and myocardial infarction. The compounds are also useful in the treatment of diabetes.
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- Jacobsen-type enantioselective hydrolysis of aryl glycidyl ethers. 31P NMR analysis of the enantiomeric composition of oxiranes
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The enantioselective partial hydrolysis of a number of racemic aryl glycidyl ethers in the presence of chiral Co(salen)-catalyst was studied. The enantiomeric composition of the isolated (R)-aryl glycidyl ethers was analyzed by 31P NMR using optically active substituted 2-chloro-1,3,2- dioxaphospholanes. A synthesis of β-adrenoblocking agents (S)-toliprolol and (S)-moprolol based on the simultaneously obtained (S)-3-aryloxypropane-1,2- diols was proposed.
- Bredikhin,Strunskaya,Novikova,Azancheev,Sharafutdinova,Bredikhina
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p. 213 - 218
(2007/10/03)
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- A Second-Generation Synthesis of the C1-C28 Portion of the Altohyrtins (Spongistatins)
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A practical second-generation synthesis of an advanced intermediate in our total synthesis of altohyrtin C (spongistatin 2) has been developed. A new approach to the C1-C15 (AB) portion features a vinyllithium addition to an aldehyde followed by a palladium-catalyzed allylic reduction to install the troublesome C13-C15 segment. Our general approach to the C16-C28 (CD) spiroketal has been retained, but some improvements have been made. Most notably, the kinetically controlled CD-spiroketalization reaction now proceeds in high yield with excellent diastereoselection. This new strategy uses the anti-aldol coupling used in our first-generation synthesis to join AB and CD fragments. A total of 9.6 g of intermediate 57 has been produced using this improved route.
- Hubbs, Jed L.,Heathcock, Clayton H.
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p. 12836 - 12843
(2007/10/03)
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- Synthesis of the C1-C12 fragment of fostriecin
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(Matrix presented) The synthesis of the C1-C12 fragment of fostriecin was achieved from (S)-glycidol in 15 steps by using an enantioselective allytitanation reaction and a ring-closure metathesis as the key steps.
- Cossy, Janine,Pradaux, Fabienne,BouzBouz, Samir
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p. 2233 - 2235
(2007/10/03)
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- Recognition of the minor groove of DNA by hairpin polyamides containing α-substituted-β-amino acids
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Incorporation of the flexible amino acid β-alanine (β) into hairpin polyamides composed of N-methylpyrrole (Py) and N-methylimidazole (Im) amino acids is required for binding to DNA sequences longer than seven base pairs with high affinity and sequence selectivity. Pairing the α-substituted-β- amino acids (S)-isoserine ((S)Is), (R)-isoserine ((R)Is), β-aminoalanine (Aa), and α-fluoro-β-alanine (Fb) side-by-side with β in hairpin polyamides alters DNA binding affinity and selectivity relative to the parent polyamide containing a β/β pairing. Quantitative DNase I footprinting titration studies on a restriction fragment containing the sequences 5'- TGCNGTA-3' (N = A, T, G, and C) show that the polyamide ImPy(S)IsImPy-γ- PyPyβImPy-β-Dp (S)Is/β pairing) binds to N = T (K(a) = 4.5 x 109 M-1) in preference to N = A (K(a) = 6.2 x 108 M-1). This result stands in contrast to the essentially degenerate binding of the parent ImPyβImPy-γ- PyPyβImPy-β-Dp (β/β pairing) to N = T and N = A, and to the slight preference of ImPyβImPy-γ-PyPy(S)IsImPy-β-Dp (β/(S)Is pairing) to N = A over N = T. Additionally, this study reveals that incorporation of (R)Is, Aa, and Fb into polyamides significantly reduces binding affinity. Therefore, DNA binding in the minor groove is sensitive to the stereochemistry, steric bulk, and electronics of the substituent at the α-position of β-amino acids in hairpin polyamides containing β/β pairs.
- Floreancig, Paul E.,Swalley, Susanne E.,Trauger, John W.,Dervan, Peter B.
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p. 6342 - 6350
(2007/10/03)
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- Potent, selective aminothiazolidinediones agonists of the human β3 Adrenergic receptor
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A cloned human β3 adrenergic receptor assay was used to identify potent and selective β3 agonists. The thiazolidinedione moiety has been identified as a new pharmacophore for the human β3 adrenergic receptor. The versatility of the thiazolidinedione pharmacophore was demonstrated in both the arylethanolamine and phenylpropanolamine families of β3 agonists, where potent and selective compounds have been synthesized. Thiazolidinedione 20, a potent and selective human β3 agonist, increased thermogenesis and lowered plasma glucose levels in the db/db mice.
- Malamas,Largis,Gunawan,Li,Tillett,Han,Mulvey
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p. 164 - 177
(2007/10/03)
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- Enantioselective allyltitanation. Efficient synthesis of the C1-C14 polyol subunit of amphotericin B
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(Matrix presented) An efficient synthesis of the C1-C14 fragment of amphotericin B is described. This synthesis is based on the formation of syn-1,3-diols from enantioselective allyltitanation of unprotected β-hydroxyaldehydes.
- BouzBouz, Samir,Cossy, Janine
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p. 3975 - 3977
(2007/10/03)
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- CsF in organic synthesis. Regioselective nucleophilic reactions of phenols with oxiranes leading to enantiopure β-blockers
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The two modes of the paths in the reaction of oxiranes with phenols are completely controlled by CsF. Glycidyl nosylate undergoes exclusive substitution at the C1 position whereas the ring-opening (C-3 attack) occurs with epichlorohydrin, glycidol, and 1,2-epoxyalkanes. These reactions provide convenient access to enantiopure β-blockers.
- Kitaori, Kazuhiro,Furukawa, Yoshiro,Yoshimoto, Hiroshi,Otera, Junzo
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p. 14381 - 14390
(2007/10/03)
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- Enantioselective Synthesis of 3-Deoxy-(R)-sphingomyelin from (S)-1-(4′-Methoxyphenyl)glycerol
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(R)-3-Deoxysphingomyelin (2) was prepared from (S)-1-(4′-methoxyphenyl)-glycerol (3). The latter was converted into either p-methoxyphenyl (PMP) (S)-oxiranylmethyl ether (5) or (R)-1-(4′-methoxyphenyl)glycerol 2,3-cyclic sulfate (6). Opening of 5 with lithium pentadecyne in the presence of BF3·Et2O gave PMP (S)-2-hydroxy-4-octadecynyl ether (7) in 65percent yield. Alternatively, opening of cyclic sulfate 6 with excess lithium pentadecyne in the presence of catalytic cuprous iodide, followed by acidic workup, gave 7 in 90percent yield. After introduction of the amide group via azide displacement, reduction, and N-acylation, simultaneous reduction of the triple bond and deprotection of the PMP group by Birch reduction (Li, EtNH2) provided 3-deoxy-N-palmitoyl-(A)-ceramide (9). Finally, phosphitylation of 9, oxidation of the cyclic phosphite with bromine, followed by in situ ring opening gave a (2-bromoethyl)phosphate ester, which on quaternization with aqueous trimethylamine afforded 3-deoxy-N-palmitoyl-(R)-sphingomyelin (2) in 49percent overall yield from PMP (S)-2-hydroxy-4-octadecynyl ether (7).
- Byun, Hoe-Sup,Sadlofsky, Jason A.,Bittman, Robert
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p. 2560 - 2563
(2007/10/03)
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- RESOLUTION OF RACEMIC O-(4-METHOXYPHENYL)GLYCIDOL
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Racemic O-(4-methoxyphenyl)glycidol has been resolved in three steps by employing lipase mediated kinetic acylation of the halohydrin intermediates.
- Takano, Seiichi,Setoh, Masaki,Ogasawara, Kunio
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p. 173 - 180
(2007/10/02)
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- Asymmetric epoxidation of allyl alcohol derivatives by ω-hydroxylase from Pseudomonas oleovorans
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This paper described the application of non-heme monooxygenase system from Pseudomonas oleovorans to the syntheses of chiral 3-(benzyloxy)-, 3-(allyloxy)-, 3-(butyloxy)- and 3-(aryloxy)-1,2-epoxypropanes (6) from their corresponding allyl alcohol derivatives.The epoxides were determined to be R forms with good enantiomeric excess.The specificities of the enzymatic epoxidation of olefines and hydroxylation of the radical probe trans-2-phenyl-1-methylcyclopropane were discussed with regard to the reaction mechanism.
- Fu, Hong,Shen, Gwo-Jenn,Wong, Chi-Huey
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p. 167 - 170
(2007/10/02)
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- PRACTICAL ROUTE TO BOTH (S)- AND (R)-ENANTIOMERS OF O-(4-METHOXYPHENYL)GLYCIDOL USING (S)-1,2-O-ISOPROPYLIDENEGLYCEROL AS A COMMON PRECURSOR
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Practical route to both (R)- and (S)-enantiomers of O-(4-methoxyphenyl)glycidol is devised using (S)-1,2-O-isopropylideneglycerol as a common chiral starting material.
- Takano, Seiichi,Moriya, Minoru,Suzuki, Mahito,Iwabuchi, Yoshiharu,Sugihara, Takumichi,Ogasawara, Kunio
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p. 1555 - 1563
(2007/10/02)
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