- Preparation of Sephadex Derivatives with Optically Active Groups and Column-chromatographic Application to the Resolution of Some Cobalt(III) Complexes
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Optically active cation-exchangers were newly prepared as Sephadex derivatives derived from L-alanine, L-valine, L-aspartic acid, and L-threonine.They were applied to the column-chromatographic resolution of some cobalt(III) complexes, partial resolution being attained.
- Fujita, Miho,Sakano, Masanobu,Yoshikawa, Yuzo,Yamatera, Hideo
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Read Online
- Synthesis and Co-ordination Chemistry of the Sterically Demanding Pendant-arm Macrocycle N,N',N''-Tris-1,4,7-triazacyclononane
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The sterically demanding pendant-arm macrocycle N,N',N''-tris-1,4,7-triazacyclononane H3L has been synthesised.Owing to its bulky isopropyl arms the formation of dimeric species is prevented which is in contrast to the behaviour of the analogous ligand with methyl substituted arms, N,N',N''-tris-1,4,7-triazacyclononane (H3L').The preparation of complexes of V(IV), Cr(III), Mn(IV), Ni(II), Cu(II) and Zn(II) with H3L is described and the crystal structures and some spectroscopic properties of *H2O and 3L)> determined.
- Fallis, Ian A.,Farrugia, Louis J.,Macdonald, Norman M.,Peacock, Robert D.
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- CRYSTALLINE FORMS OF A CD73 INHIBITOR
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The present invention relates to crystalline forms of 5-[5-[2-isopropylcyclopropyl] -6-methyl-pyridazin-3-yl]-1H-pyrimidine-2,4-dione, and pharmaceutical compositions comprising them, which inhibit the activity of CD73 and are useful for treating cancer.
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Page/Page column 21
(2021/03/05)
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- A facile microwave assisted synthesis and structure elucidation of (3R)-3-alkyl-4,1-benzoxazepine-2,5-diones by crystallographic, spectroscopic and DFT studies
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The use of microwave (MW) irradiation in organic synthesis has become increasingly popular within the pharmaceutical and academic arenas because it is a new enabling technology for drug discovery and development. It is a rapid way of synthesis, which involves faster reaction rates and high selectivity to conventional heating method of syntheses. The MW-assisted 7-exo-tet cyclization of N-acylanthranilic acids afforded (3R)-3-alkyl-4,1-benzoxazepines-2,5-diones in very short duration (20 min) with extraordinary high yields in comparison to conventional heating mode of synthesis. The method development, comparative yields of MW-assisted and thermal method of syntheses, crystallographic, spectroscopic and density functional theory (DFT) studies are reported herein. Four novel compounds with chemical formulas C10H9BrClNO3 5m, C19H19NO3 6e, C13H14ClNO3 6h and C12H11Br2NO3 6h were synthesized, validated by 1HNMR, 13CNMR, FT-IR, UVVis, EIMS spectroscopic techniques and confirmed by using single crystal X-ray diffraction (SC-XRD) study. The DFT and TDDFT calculations at B3LYP/6-311 + G(d,p) level of theory were performed for comparative analysis of spectroscopic data, optimized geometries, frontier molecular orbitals (FMOs), natural bond orbital (NBO) analysis and nonlinear optical (NLO) properties of 5m, 6e, 6h and 6o. Overall, experimental findings were supported nicely by corresponding DFT computed results. The NBO analysis confirmed that the presence of non-covalent interactions, hydrogen bonding and hyper- conjugative interactions are pivotal cause for the existence of 5m, 6e, 6h and 6o in the solid-state. NLO analysis showed that 5m, 6e, 6h and 6o have significant NLO properties as compared to prototype standard compound which disclosed their potential for technology related applications.
- Raza, Abdul Rauf,Nisar, Bushra,Khalid, Muhammad,Gondal, Humaira Yasmeen,Khan, Muhammad Usman,de Alcantara Morais, Sara Figueirêdo,Tahir, Muhammad Nawaz,Braga, Ataualpa Albert Carmo
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- CD73 INHIBITORS
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The present invention provides 5-[5]-[2-cycloa Ikyl ]-6-pyridazin-3-yl ]- IH-pyrimidine-2,4-dione compounds, or pharmaceutically acceptable salts thereof, that inhibit the activity of CD73 and are useful in treating cancer. (Formula (I))
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Page/Page column 38
(2019/09/18)
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- Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide A
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The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram-negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β-selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re-examination of its activity against bacterial pathogens, and only minimal activity was observed.
- Hattori, Hiromu,Roesslein, Joel,Caspers, Patrick,Zerbe, Katja,Miyatake-Ondozabal, Hideki,Ritz, Daniel,Rueedi, Georg,Gademann, Karl
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supporting information
p. 11020 - 11024
(2018/07/31)
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- Di(1-naphthyl) methanol ester of carboxylic acids for absolute stereochemical determination
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The absolute stereochemistry of chiral carboxylic acids is determined as a di(1-naphthyl)methanol ester derivative. Computational scoring of conformations favoring either P or M helicity of the naphthyl groups, capable of exciton-coupled circular dichroic coupling, leads to a predicted stereochemistry for the derivatized carboxylic acids.
- Zhang, Jun,Sheng, Wei,Gholami, Hadi,Nehira, Tatsuo,Borhan, Babak
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supporting information
p. 141 - 146
(2017/11/13)
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- Chiral Pool-Based Synthesis of Naphtho-Fused Isocoumarins
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A variety of chiral derivatives of benzo[d]naphtho[1,2-b]pyran-6-one were prepared in a single step by Et3N-mediated condensation of homophthalic anhydride with different derivatives of (S)-amino acid chlorides at -5 °C by employing a chiral pool methodology. Chirality 27:951-957, 2015.
- Raza, Abdul Rauf,Saddiqa, Aisha,?akmak, Osman
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p. 951 - 957
(2015/11/16)
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- Forming Stereogenic Centers in Acyclic Systems from Alkynes
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The combined carbometalation/zinc homologation followed by reactions with α-heterosubstituted aldehydes and imines proceed through a chair-like transition structure with the substituent of the incoming aldehyde residue preferentially occupying a pseudo-axial position to avoid the two gauche interactions. The heteroatom in the axial position produces a chelated intermediate (and not a Cornforth-Evans transition structure for α-chloro aldehydes and imines) leading to a face differentiation in the allylation reaction. This method provides access to functionalized products in which three new carbon-carbon bonds and two to three stereogenic centers, including a quaternary one, were created in acyclic systems in a single-pot operation from simple alkynes. All-carbon quaternary stereocenter: The combined carbometalation/zinc homologation of alkynes followed by reactions with α-heterosubstituted aldehydes and imines provides access to functionalized acyclic adducts. These adducts obtained in a single-pot reaction have three new carbon-carbon bonds and two to three stereogenic centers, including a quaternary carbon stereocenter.
- Vabre, Roxane,Island, Biana,Diehl, Claudia J.,Schreiner, Peter R.,Marek, Ilan
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supporting information
p. 9996 - 9999
(2015/08/19)
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- Chiron based synthesis of isocoumarins: Reactivity of α-substituted carboxylic acids
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The asymmetric synthesis of a novel (S)-isocoumarin has been attempted in a single step by the coupling of homophthalic acid with (S)-N-protected amino acids and α-chloroacids at high temperature by exploiting a chiral pool methodology. The coupling of homophthalic acid with N-protected (S)-amino acids gave exclusion of the carboxyl/alkyl group. However, coupling of homophthalic acid with α-chloroacids afforded asymmetric isocoumarins in high yield.
- Saddiqa, Aisha,Raza, Abdul R.,Black, David Stc.,Kumar, Naresh
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p. 736 - 743
(2014/06/09)
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- Comparative molecular field analysis of fenoterol derivatives interacting with an agonist-stabilized form of the β2-adrenergic receptor
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The β2-adrenergic receptor (β2-AR) agonist [3H]-(R,R′)-methoxyfenoterol was employed as the marker ligand in displacement studies measuring the binding affinities (Ki values) of the stereoisomers of a series of 4′-methoxyfenoterol analogs in which the length of the alkyl substituent at α′ position was varied from 0 to 3 carbon atoms. The binding affinities of the compounds were additionally determined using the inverse agonist [3H]-CGP-12177 as the marker ligand and the ability of the compounds to stimulate cAMP accumulation, measured as EC50 values, were determined in HEK293 cells expressing the β2-AR. The data indicate that the highest binding affinities and functional activities were produced by methyl and ethyl substituents at the α′ position. The results also indicate that the Ki values obtained using [3H]-(R,R′)-methoxyfenoterol as the marker ligand modeled the EC50 values obtained from cAMP stimulation better than the data obtained using [3H]-CGP-12177 as the marker ligand. The data from this study was combined with data from previous studies and processed using the Comparative Molecular Field Analysis approach to produce a CoMFA model reflecting the binding to the β2-AR conformation probed by [3H]-(R,R′)-4′-methoxyfenoterol. The CoMFA model of the agonist-stabilized β2-AR suggests that the binding of the fenoterol analogs to an agonist-stabilized conformation of the β2-AR is governed to a greater extend by steric effects than binding to the [3H]-CGP-12177-stabilized conformation(s) in which electrostatic interactions play a more predominate role.
- Plazinska, Anita,Pajak, Karolina,Rutkowska, Ewelina,Jimenez, Lucita,Kozocas, Joseph,Koolpe, Gary,Tanga, Mary,Toll, Lawrence,Wainer, Irving W.,Jozwiak, Krzysztof
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p. 234 - 246
(2014/01/17)
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- Synthesis of four stereoisomers of (S)-2-methylpent-3-yl 3,13-dimethylpentadecanoate, a sex pheromone of the bagworm moth clania variegate, using stereospecific inversion of secondary sulfonates as a key step
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Females of some lepidopteran species produce novel sex pheromones with a methyl-branched structure, such as 2-methylpent-3-yl 3,13-dimethylpentadecanoate secreted by the bagworm moth Clania variegate. Recently, we have established a simple preparative method for the synthesis of methyl-branched building blocks by utilizing an SN2 reaction of chiral secondary tosylates derived from (S)- and (R)-propylene oxides. The usefulness of these building blocks was demonstrated by their application in the synthesis of all four stereoisomers of an acid moiety in the bagworm pheromone. The enantiomeric purities of all building blocks were confirmed by enantioselective HPLC analysis. We found that a secondary mesylate was superior to the corresponding tosylate because it avoided an elimination side reaction, and racemization in the SN2 reaction was not observed even at high temperature (150 °C). Finally, each optically active acid was esterified with (S)-2-methyl-3-pentanol, which was synthesized by a new route starting from (S)-valine. A simple route to methyl-branched building blocks has been developed by utilizing an S N2 reaction of chiral secondary sulfonates derived from (S)- and (R)-propylene oxides. The usefulness of these building blocks was demonstrated by the stereospecific synthesis of all four stereoisomers of a bagworm pheromone. Copyright
- Taguri, Tomonori,Yamamoto, Masanobu,Fujii, Toru,Muraki, Yuta,Ando, Tetsu
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p. 6924 - 6933
(2013/11/06)
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- Stereoselective synthesis of (3r)-3-alkyl-4,1-benzoxazepine-2,5-diones
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Novel 3-alkyl-4,1-benzoxazepine-2,5-diones were synthesized in good ee exploiting the chiral pool methodology, an economical way of asymmetric synthesis. Various anthranilic acids are coupled with different α-haloacids to afford N-acylated anthranilic aci
- Nisar, Bushra,Raza, Abdul Rauf,Black, David Stc.,Kumar, Naresh,Tahir, Muhammad Nawaz
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p. 865 - 870
(2014/01/06)
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- Conformational preference in bis(porphyrin) tweezer complexes: A versatile chirality sensor for α-chiral carboxylic acids
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Metallated porphyrin tweezers have demonstrated a remarkable ability to function as reporters of absolute stereochemistry for a number of different classes of organic molecules. Flexibility in binding, however, can result in an ensemble of different Exciton Coupled Circular Dichroism (ECCD) active conformations that could lead to variable results. Linker flexibility was found to be a key determinant of binding conformation. Experimental results indicate that a balance between linker flexibility and rigidity could yield an optimum porphyrin tweezer that stabilizes a common conformation for all bound chiral guests. This leads to a more simplified approach to absolute stereochemical determination of asymmetry for small organic molecules. This was demonstrated by the use of a C3-linked zincated porphyrin tweezer that yields a common conformational preference for a variety of α-chiral carboxylic acids derivatized with a diamine carrier. Copyright
- Tanasova, Marina,Borhan, Babak
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supporting information; experimental part
p. 3261 - 3269
(2012/07/01)
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- Synthesis of azide-alkyne fragments for "Click" chemical applications. Part 2. Formation of oligomers from orthogonally protected chiral trialkylsilylhomopropargyl azides and homopropargyl alcohols
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(Chemical Equation Presented) A small library of chiral, β3-substituted homopropargyl alcohols and chiral β3-substituted trimethylsilylhomopropargyl azides were generated starting from natural L-amino acids. The free alkynes and azides were then coupled, using a Huisgen 1,3-dipolar cycloaddition, to provide chiral oligomeric 1,4-disubstituted-1,2,3-triazoles as potential peptidomimetic compounds. The work is an extension to the previous synthesis of racemic, orthogonally protected 1,4-disubstituted-1,2,3-triazoles from the corresponding α-substituted propargyl alcohols and α-substituted trialkylsilylpropargyl azides.
- Montagnat, Oliver D.,Lessene, Guillaume,Hughes, Andrew B.
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scheme or table
p. 390 - 398
(2010/03/30)
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- Stereoselective synthesis of chiral 4-(1-Chloroalkyl)-β-lactams starting from amino acids and their transformation into functionalized chiral azetidines and pyrrolidines
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Chiral short-chain α-chloroaldehydes were prepared starting from enantiomerically pure amino acids in a three-step approach, thus providing a practical synthetic alternative for known organocatalytic α-chlorination procedures. The latter aldehydes proved
- Dekeukeleire, Stijn,Dhooghe, Matthias,Toernroos, Karl W.,De Kimpe, Norbert
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experimental part
p. 5934 - 5940
(2010/11/05)
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- An unusual conformation of α-haloamides due to cooperative binding with zincated porphyrins
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CD and NMR spectroscopic evidence of cooperative binding between an α-halogen atom and a carboxamide group with a zinc porphyrin leads to an unprecedented conformation for the determination of the absolute stereochemistry of α-haloamides (α-halocarboxylic acids derivatized with 1,4-phenylenediamine) through the use of exciton-coupled circular dichroism (ECCD). With the use of chiral lactams, whose rotomeric contributions are minimized, both ECCD and NMR spectroscopy demonstrate that the porphyrin favors binding to the side of the sterically more demanding halogen atom as compared to the smaller hydrogen atom. In all, the data is strongly suggestive of an unusual conformation not observed before for α-chiral amides. A mnemonic for determining the absolute stereochemistry of α-halogenated carboxylic acids is provided.
- Tanasova, Marina,Yang, Qifei,Olmsted, Courtney C.,Vasileiou, Chrysoula,Li, Xiaoyong,Anyika, Mercy,Borhan, Babak
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supporting information; experimental part
p. 4242 - 4253
(2011/02/25)
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- Liquid crystal dimers derived from naturally occurring chiral moieties: synthesis and characterization
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Naturally occurring cholesterol and α-chloroalkanoyl units derived from natural α-amino acids (l-valine, l-leucine, and l-isoleucine) have been utilized to prepare three different series of nonsymmetric liquid crystal dimers. Tolane (diphenylacetylene), w
- Yelamaggad, Channabasaveshwar V.,Shanker, Govindaswamy
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p. 3760 - 3771
(2008/09/20)
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- C,C-Coupling with sulfur-stabilized carbanions - 6. Preparation and electrophilic substitution of 1-[3-methyl-2-(2-thioanylthio)-butyl]piperidine and dethioacetalization of semicyclic dithioacetals
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1-[3-Methyl-2-(2-thioanylthio)butyl]piperidine (8) is obtained from L-valine via enantiomerically pure 1-(2-mercapto-3-methylbutyl)piperidine (6). The diastereoisomers are separated by column chromatography and the reactions of the carbanion 8a with elect
- Birk, Claudia,Voss, Juergen
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p. 12745 - 12760
(2007/10/03)
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- Asymmetric Synthesis of 2-Chloro- and 2-Bromo-alkanoic acids by Halogenation of α-D-Glucofuranose-Derived Silyl Ketene Acetals.
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Optically active (S)-2-bromo- and 2-chloro-alkanoic acids 6 and 7 have been obtained via the diastereoselective halogenation of chiral silyl ketene acetals 3a-f, and subsequent saponification of the resulting crude esters.Examples characterized by e.e. values up to 95percent are reported.The diastereoface selectivity is independent of the silyl ketene acetal E/Z configuration.
- Angibaud, P.,Chaumette, J. L.,Desmurs, J. R.,Duhamel, L.,Ple, G.,et al.
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p. 1919 - 1932
(2007/10/03)
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- Synthesis and study of new α-haloacid ferroelectric liquid crystal derivatives. MM2 approach to the molecular structure-ferroelectric activity relationship
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In order to understand the structural factors that influence ferroelectric properties, three new series (F, Cl, and Br) of chiral naphthalene-ring derived compounds were synthesized, and their ferroelectric properties [spontaneous polarization (Ps) and response time (τ)] were evaluated in the pure compound. The chiral tails are α-halo acids derived from L-α-amino acids: L-α-alanine (1), L-leucine (2), L-isoleucine (3), and L-valine (4), with a fluorine, chlorine, or bromine atom in the chiral center. The highest Ps values were obtained for compounds containing a fluorine or chlorine atom in their asymmetric center and with chiral tail derived from L-isoleucine (3) (F-3, 102 nC/cm2; Cl-3, 100 nC/cm2). The steric requirements of the halogen atom and the bulky alkyl group in the asymmetric center determine the most stable conformations of these chiral tails, which have been studied by molecular mechanic empirical calculations, MM2. MM2 calculations prove to be a successful tool for understanding how the structure of the lateral chiral tail affects molecular arrangement and, as a consequence, the ferroelectric properties of the materials.
- Sierra,Serrano,Ros,Ezcurra,Zubía
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p. 7645 - 7651
(2007/10/02)
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- Enantiomeric Recognition of Organic Ammonium Salts by Chiral Dialkyl-, Dialkenyl-, and Tetramethyl-Substituted Pyridino-18-crown-6 and Tetramethyl-Substituted Bis-pyridino-18-crown-6 Ligands: Comparison of Temperature-Dependent 1H NMR and Empirical Force
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Six new chiral pyridino-18-crown-6 and one chiral bis-pyridino-18-crown-6 ligands have been prepared.The pyridino-crowns contain either two isopropyl, two isobutyl, two (S)-sec-butyl, two benzyl, two 3-butenyl, or four methyl substituents on chiral macror
- Bradshaw, Jerald S.,Huszthy, Peter,McDaniel, Christopher W.,Zhu, Cheng Y.,Dalley, N. Kent,et al.
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p. 3129 - 3137
(2007/10/02)
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- The Determination of Small Amounts of Enantiomeric Impurities in α-Halo Carboxylic Acids
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The accurate determination of the enantiomeric composition of α-halo carboxylic acids is reported.Such data are of importance in the synthesis of chiral compounds and in mechanistic studies involving the title compounds.
- Watabe, K.,Chang, S.-C.,Gil-Av, E.,Koppenhoefer, B.
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p. 225 - 228
(2007/10/02)
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