- PANTETHEINE DERIVATIVES AND USES THEREOF
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The present disclosure relates to compounds of Formula (I), (II), or (II'): (I), (II), (II'), and pharmaceutically acceptable salts or solvates thereof. The present disclosure also relates to pharmaceutical compositions comprising the compounds and therapeutic and diagnostic uses of the compounds and pharmaceutical compositions.
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Paragraph 2121
(2020/06/19)
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- Hansforesters A-M, polyesters from the sponge-associated fungus Hansfordia sinuosae with antibacterial activities
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Bioassay-guided fractionation and chromatographic separation of a sponge-derived fungus Hansfordia sinuosae, resulted in the isolation of thirteen new polyesters namely hansforesters A-M (1-13), along with five known analogues involving ascotrichalactone A, ascotrichester B, 15G256π, 6R-hydroxymellein, and (?)orthosporin. The structures of the new compounds were determined through extensive spectroscopic analysis, in addition to the chemical conversion for the configurational assignment. The polyesters incorporating the motifs of orsellinic acid, 2,4-dihydroxy-6-acetonylbenzoic acid, and orcinotriol were found from nature for the first time. Hansforester A (1) and ascotrichalactone A exhibited potent inhibition against a panel of bacterial strains, including the agricultural pathogenic bacteria, Pseudomonas lachrymans, Agrobacterium tumefaciens, Xanthomonas vesicatoria, and Ralstonia solanacearum, with the MIC values of 15.6 μM, and the human infected bacterium Staphylococcus aureus with the MIC values of 3.9 μM. These findings suggested that hansforester A and ascotrichalactone A are the potential leads to be developed as the antibacterial agents for the treatment of agriculture bacterial pathogens.
- Wu, Zehong,Liu, Dong,Huang, Jian,Proksch, Peter,Zhu, Kui,Lin, Wenhan
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p. 39756 - 39768
(2018/12/13)
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- Synthesis process of (R)-3-hydroxybutyric acid and salts thereof
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The invention discloses a synthesis process for preparing (R)-3-hydroxybutyric acid and sodium salt, potassium salt, magnesium salt and calcium salt thereof. The process includes steps: adding 3-oxobutanoate and a ruthenium complex catalyst into organic solvent according to a mole ratio of 1:0.0005-0.005, and reacting at 20-80 DEG C for 12-24h under a hydrogen pressure of 1-20bar to obtain (R)-3-hydroxybutyrate; dissolving (R)-3-hydroxybutyrate into water, and subjecting to reaction with sodium hydroxide, potassium hydroxide or calcium hydroxide for 2-12h at a low temperature to obtain sodium salt, potassium salt, magnesium salt and calcium salt of (R)-3-hydroxybutyric acid; subjecting water solution of (R)-3-sodium hydroxybutyrate to 732 cation exchange resin treatment to remove sodium ions to obtain (R)-3-hydroxybutyric acid; subjecting (R)-3-hydroxybutyric acid to reaction with magnesium hydroxide to obtain (R)-3-magnesium hydroxybutyrate. Ee values of (R)-3-hydroxybutyric acid and sodium salt, potassium salt, magnesium salt and calcium salt thereof reach 90% or above. The method has advantages of low environment pollution, low cost and easiness in aftertreatment.
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Paragraph 0048; 0049
(2017/10/07)
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- Novel urushiols with human immunodeficiency virus type 1 reverse transcriptase inhibitory activity from the leaves of Rhus verniciflua
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Two novel urushiols, 1 and 2, and two known urushiols, 3 and 4, were isolated from the leaves of Rhus verniciflua and were examined for their human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitory activity. The novel urushiols were found to be 1,2-dihydroxyphenyl-3-[7(E),9(Z),11(Z)-pentadecatrienyl]-14-ol (1) and 1,2-dihydroxyphenyl-3-[8(Z),10(E),12(E)-pentadecatrienyl]-14-ol (2) by spectroscopic analyses. The absolute configuration at C-14 in 1 and 2 was determined to be a racemic mixture of (R) and (S) isomers by ozonolysis. Compound 2 (IC50: 12.6 μM) showed the highest HIV-1 RT inhibitory activity among the four urushiols, being 2.5-fold more potent than the positive control, adriamycin (IC50: 31.9 μM). Although the known urushiols were isolated from the sap and leaves of R. verniciflua, 1 was exclusively present in the leaves, and higher amounts of 2 were found in the leaves than in the sap. Present findings indicate that the leaves of R. verniciflua represent a new biological resource from which novel and known urushiols may be prepared, and the possible use of novel urushiols as bioactive products.
- Kadokura, Kazunari,Suruga, Kohei,Tomita, Tsuyoshi,Hiruma, Wataru,Yamada, Motoyuki,Kobayashi, Akio,Takatsuki, Akira,Nishio, Toshiyuki,Oku, Tadatake,Sekino, Yoshihiro
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p. 148 - 153
(2015/02/19)
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- A high throughput screening strategy for the assessment of nitrile-hydrolyzing activity towards the production of enantiopure β-hydroxy acids
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Nitrile hydrolysing enzymes have found wide use in the pharmaceutical industry for the production of fine chemicals. This work presents a strategy that facilitates the rapid identification of bacterial isolates demonstrating nitrile hydrolysing activity. The strategy incorporates toxicity, starvation and induction studies along with subsequent colorimetric screening for activity, further focusing the assessment towards the substrates of interest. This high-throughput strategy uses a 96 well plate system, and has enabled the rapid biocatalytic screening of 256 novel bacterial isolates towards β-hydroxynitriles. Results demonstrate the strategy's potential to rapidly assess a variety of β-hydroxynitriles including aliphatic, aromatic and dinitriles. A whole cell catalyst Rhodococcus erythropolis SET1 was identified and found to catalyse the hydrolysis of 3-hydroxybutyronitrile with remarkably high enantioselectivity under mild conditions, to afford (S)-3-hydroxybutyric acid in 42% yield and >99.9% ee. The biocatalytic capability of this strain including the variation of parameters such as temperature and time were further investigated and all results indicate the presence of a highly enantioselective if not enantiospecific nitrilase enzyme within the microbial whole cell.
- Coady, Tracey M.,Coffey, Lee V.,O'Reilly, Catherine,Owens, Erica B.,Lennon, Claire M.
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p. 150 - 155
(2013/10/01)
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- Syntheses of mycobactin analogs as potent and selective inhibitors of Mycobacterium tuberculosis
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Three analogs of mycobactin T, the siderophore secreted by Mycobacterium tuberculosis (Mtb) were synthesized and screened for their antibiotic activity against Mtb H37Rv and a broad panel of Gram-positive and Gram-negative bacteria. The synthetic mycobactins were potent (MIC90 0.02-0.88 μM in 7H12 media) and selective Mtb inhibitors, with no inhibitory activity observed against any other of the microorganisms tested. The maleimide-containing analog 40 represents a versatile platform for the development of mycobactin-drug conjugates, as well as other applications.
- Juárez-Hernández, Raúl E.,Franzblau, Scott G.,Miller, Marvin J.
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p. 7584 - 7593
(2012/10/29)
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- Total syntheses of the gregatins A-D and aspertetronin A: Structure revisions of these compounds and of aspertetronin B, together with plausible structure revisions of gregatin E, cyclogregatin, graminin A, the penicilliols A and B, and the huaspenones A and B
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Comprehensive comparisons of 1H and 13C NMR chemical shift values in the furanone cores a, b, and c provide plausible support for a reassessment of the furanone nuclei of the title compounds from b to c. Total syntheses via enantiomerically pure lactic esters were based on the Seebach-Frater "self-reproduction of stereocenters" methodology. Attachment of the hexadienyl side-chain in a trans,trans-selective manner was achieved by addition of the Seebach-Frater enolate to trans-hex-4-en-1-al rather than to trans-hex-3-en-1-al. The type-c furanone cores of the synthetic materials were reached by single or double acylation of a model γ-hydroxy-β-oxo ester (compound 50) and its hexadiene-containing counterpart 29. Our syntheses confirmed the novel connectivities in six compounds. In addition, they required revision of the configuration of a quaternary carbon atom in five cases. Moreover, they allowed elucidation of the configurations of four previously unassigned stereocenters. Hindsight analyses of why the furanone cores of the title compounds had been misinterpreted as a and/or b instead of c are given. Why the stereocenters in the heterocycles had been incorrectly configured, on the bases (a) of relay studies in the 1960s, and (b) of a 1984 total synthesis of gregatin B, is also discussed.
- Burghart-Stoll, Heike,Brueckner, Reinhard
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supporting information; experimental part
p. 3978 - 4017
(2012/10/18)
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- Mycenaaurin A, an antibacterial polyene pigment from the fruiting bodies of mycena aurantiomarginata
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A new polyene pigment, mycenaaurin A (1), was isolated from fruiting bodies of Mycena aurantiomarginata. Mycenaaurin A consists of a tridecaketide that is flanked by two amino acid moieties. These are likely to be derived biosynthetically from S-adenosylmethionine. The tridecaketide itself contains an α-pyrone, a conjugated hexaene, and an isolated alkenyl moiety. The structure of the new pigment was established by 2D NMR spectroscopic methods and APCIMS. The absolute configuration of the four stereogenic centers was determined by degradation of 1 by ozonolysis and GC-MS comparison of the resulting fragments, after appropriate derivatization, with authentic synthetic samples. Mycenaaurin A (1) might act as a constitutive defense compound, since it exhibits antibacterial activity against the Gram-positive bacterium Bacillus pumilus.
- Jaeger, Robert J. R.,Spiteller, Peter
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experimental part
p. 1350 - 1354
(2010/10/21)
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- Asymmetric hydrolysis of 2-hydroxy-carboxylic esters using recombinant Escherichia coli
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Optically active 2-hydroxy-carboxylates are important compounds for their use as intermediates in the synthesis of pharmaceuticals and stereoblock polymers. Enterobacter sp. DS-S-75 and the recombinant Escherichia coli harbouring the 4-chloro-3-hydroxybutyrate (CHB) hydrolase gene from the strain DS-S-75 showed asymmetric hydrolytic activity towards 2-hydroxy-carboxylates, as well as towards CHB. It was discussed that the hydroxyl group in the substrate was particularly important for the asymmetric hydrolytic activity of the CHB hydrolase, and as such, it was re-designated to EnHCH (hydroxy-carboxylic ester hydrolase derived from Enterobacter sp.). Using the recombinant cell, both the reaction rate and the concentration of the substrates were significantly improved upon when compared to that of DS-S-75. Optically active 2-hydroxy-carboxylates could be synthesized on a practical basis for industrial production in this report.
- Nakagawa, Atsushi,Kato, Ko,Shinmyo, Atsuhiko,Suzuki, Toshio
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p. 2394 - 2398
(2008/03/13)
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- KETOGENIC SACCHARIDES
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A novel ketogenic compound is provided having general formula (R(OCH(CH3)CH2C(O))nO)m-A wherein n is a integer between I and 10, m is an integer of 1 to 200,000, A is a monsaccharide, polysaccharide or oligosaccharide residue and R is selected from the group consisting of H, C1-C6 alkyl and acetoacetyl-
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Page/Page column 8
(2008/06/13)
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- Carnitine-esters from the mushroom Suillus laricinus
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Carnitine-esters (1-8) including, a compound (R)-3-hydroxybutanoyl-(R)-carnitine (5), were isolated from the mushroom Suillus laricinus. Their structures were determined by spectroscopic analyses and by total synthesis. One of these, (R)-3-hydroxy-2-methylpropanoyl-(R)-carnitine (4), promoted hyaluronan-degradation by human skin fibroblasts.
- Kawagishi, Hirokazu,Murakami, Hiroaki,Sakai, Shingo,Inoue, Shintaro
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p. 2676 - 2680
(2007/10/03)
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- Assembly intermediates in polyketide biosynthesis: Enantioselective syntheses of β-hydroxycarbonyl compounds
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A versatile approach for the enantioselective synthesis of functionalised β-hydroxy N-acetylcysteamine thiol esters has been developed which allows the facile incorporation of isotopic labels. It has been shown that a remarkable reversal of selectivity occurs in the titanium mediated aldol reaction of acyloxazolidinone 7 using either (S)- or (R)-tert-butyldimethylsilyloxybutanal. The aldol products are valuable intermediates in the synthesis of 4-hydroxy-6-substituted δ-lactones. The Royal Society of Chemistry 2005.
- Sann, Christine Le,Munoz, Dulce M.,Saunders, Natalie,Simpson, Thomas J.,Smith, David I.,Soulas, Florilene,Watts, Paul,Willis, Christine L.
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p. 1719 - 1728
(2007/10/03)
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- Protic acid-catalyzed polymerization of β-lactones for the synthesis of chiral polyesters
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Chiral poly(β-hydroxybutyrate) was prepared with retention of configuration from (R)-β-butyrolactone by ring-opening polymerization catalyzed by triflic acid in an aprotic solvent. At higher temperatures, triflic acid could also be used to depolymerize ch
- Jaipuri, Firoz A.,Bower, Brian D.,Pohl, Nicola L.
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p. 3249 - 3252
(2007/10/03)
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- Selective reductions. 59. Effective intramolecular asymmetric reductions of α-, β-, and γ-keto acids with diisopinocampheylborane and intermolecular asymmetric reductions of the corresponding esters with B-chlorodiisopinocampheylborane
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A comparison of the stereochemistry of the products obtained from the intramolecular asymmetric reduction of a series of keto acids with (-)-diisopinocampheylborane and intermolecular asymmetric reduction of the corresponding series of keto esters with (-)-B-chlorodiisopinocampheylborane ((-)-DIP-Chloride) has been made. The stereochemistry of the hydroxy acids from the reduction of keto acids is dependent only on the enantiomer of the reagent used. The stereochemistry of the products from the reduction of keto esters is also consistent, except those of aliphatic α-keto esters. α-, β-, and γ-keto acids provide the corresponding hydroxy acids in 77-98% ee, and the α- and γ-keto esters afford the hydroxy esters in 82-≥99% ee. β-Keto esters do not undergo reduction. Although the reduction of δ-keto acids does not proceed under the same reaction conditions, the reduction of δ-keto esters is facile. All of the products from the reduction of γ-keto acids and esters and δ-keto esters were converted to the corresponding lactones. This study revealed that DIP-Chloride is an efficient reagent for the reduction of α-keto esters at low temperatures.
- Ramachandran, P. Veeraraghavan,Pitre, Sangeeta,Brown, Herbert C.
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p. 5315 - 5319
(2007/10/03)
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- Mapping the substrate selectivity of new hydrolases using colorimetric screening: Lipases from Bacillus thermocatenulatus and Ophiostoma piliferum, esterases from Pseudomonas fluorescens and Streptomyces diastatochromogenes
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Recent advances in biochemistry and molecular biology have simplified the discovery and preparation of new hydrolases. Although these hydrolases might solve problems in organic synthesis, measuring their selectivity, especially enantioselectivity, remains tedious and time consuming. Recently, we developed a colorimetric screening method to measure the enantioselectivity of hydrolases. Here we apply this rapid screening method to map the substrate selectivity of four new hydrolases: lipases from the thermophilic Bacillus thermocatenulatus (DSM 730, BTL2) and a filamentous fungus Ophiostoma piliferum (NRRL 18917, OPL) and esterases from two bacteria, Pseudomonas fluorescens (SIK-W1, esterase I, PFE) and Streptomyces diastatochromogenes (Tue 20, SDE). We screened a general library of 29 substrates and a chiral library of 23 pairs of enantiomers. All four hydrolases catalysed the hydrolysis of unnatural substrates, but the two lipases accepted a broader range of substrates than the two esterases. As expected, the two lipases favoured more hydrophobic substrates, while the two esterases showed a preference for smaller substrates. Several moderately enantioselective reactions were identified for the solketal esters: BTL2, butyrate, E = 7.9 (R); octanoate, E = 4.9 (R) and 3-bromo-2-methyl propionate methyl esters, PFE, E = 12 (S); SDE, E = 5.6 (S). OPL showed low enantioselectivity toward all substrates tested. The current colorimetric screen could not measure the selectivity for several slow-reacting substrates. Traditional screening identified high enantioselectivity of BTL2 and PFE toward one of these slow substrates, 1-phenylethyl acetate (E>50).
- Liu, Andrew Man Fai,Somers, Neil A.,Kazlauskas, Romas J.,Brush, Terry S.,Zocher, Frank,Enzelberger, Markus M.,Bornscheuer, Uwe T.,Horsman, Geoff P.,Mezzetti, Alessandra,Schmidt-Dannert, Claudia,Schmid, Rolf D.
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p. 545 - 556
(2007/10/03)
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- Absolute stereostructures of cell-adhesion inhibitors, macrosphelides C, E-G and I, produced by a Periconia species separated from an Aplysia sea hare
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Macrosphelides E-I have been isolated, along with known macrosphelides A and C, from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai, and the absolute stereostructures of macrosphelides E-G and I have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations. In addition, the absolute configuration of macrosphelide C, previously undetermined, has been established by X-ray analysis and application of the modified Mosher method. Macrosphelides E-H inhibited the adhesion of human-leukaemia HL-60 cells to HUVEC.
- Yamada,Iritani,Doi,Minoura,Ito,Numata
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p. 3046 - 3053
(2007/10/03)
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- Efficient intramolecular asymmetric reductions of α-, β-, and γ-keto acids with diisopinocampheylborane1
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(equation presented) α-, β-, and γ-Keto acids are reduced with diisopinocampheylborane at room temperature to the corresponding hydroxy acids with predictable stereochemistry in very high ee. The γ-hydroxy acids produced were conveniently cyclized to the corresponding lactones. This provides a simple synthesis of 4-hexanolide, a component of the pheromone secreted by the female dermestid beetle Trogoderma glabrum.
- Veeraraghavan Ramachandran,Brown, Herbert C.,Pitre, Sangeeta
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- Optically active compound, liquid crystal composition containing the same, and liquid crystal electro-optic element using the same
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An optically active compound represented by formula (I): wherein A represents wherein R2 represents an alkyl group having from 8 to 12 carbon atoms; R1 represents a straight chain alkyl group having from 2 to 5 carbon atoms; X represents a fluorine atom or a methyl group; n represents 1 or 2; m represents an integer of from 0 to 3; and C* represents an asymmetric carbon atom, and a liquid crystal composition containing the same are disclosed. The compound exhibits large spontaneous polarization and low viscosity and, when added to an achiral base liquid crystal composition, induces a chiral nematic phase in which the helical pitch has small temperature dependence.
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- Synthesis and structure of linear and cyclic oligomers of 3- hydroxybutanoic acid with specific sequences of (R)- and (S)-configurations
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To study the stereoselectivity of enzymatic cleavage of poly(3- hydroxybutyrates) (PHB) in a well-defined system (purified depolymerase and monodisperse substrate of specific relative configuration), linear and cyclic oligomers of HB (OHBs) containing (R)- and (S)-3-hydroxybutanoate residues were synthesized. The starting material (R)-HB was prepared from natural sPHB, and (S)-HB by enantioselective reduction of 3- oxobutanoate with yeast or with H2/Noyori-Taber catalyst (Scheme2). The HB building blocks were then prolected (O-benzyl/tert-butyl ester; Scheme 3) and coupled to give dimers 3, 4, tetramers 5-9, and octamers 10-18; for analytical comparison, a 3mer, 5mer, 6mer, and 7mer (19-22) were also prepared. Two of the tetramers were subjected to macrolactonization conditions (Yamaguchi) to give the cyclic tetramers 23 and 25 and octamers 24 and 26. All new compounds were fully characterized (m.p., [α](D), CD, IR, 1H- and 13C-NMR, MS, elemental analysis). Single-crystal X-ray structure analyses were performed with oligolides 24 and 25 (Figs. 2 and 4), and the structures, as well as the crystal packing, were compared with those of analogs containing only (R)-HB units or consisting of 3-amino- instead of 3-hydroxybutanoic-acid moieties.
- Bachmann, Beat M.,Seebach, Dieter
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p. 2430 - 2461
(2007/10/03)
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- Novel antitumour metabolites produced by a fungal strain from a sea hare
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Pericosines A (1) and B (2), and macrosphelides E - H (3 - 6) have been isolated, along with known macrosphelide C (7), from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai, and their structures have been established on the basis of spectral analyses. Compounds 1 and 2 exhibited significant inhibitory activity in vitro against tumour cells, and the former also showed significant in vivo tumour-inhibitory activity.
- Numata, Atsushi,Iritani, Masashi,Yamada, Takeshi,Minoura, Katsuhiko,Matsumura, Eiko,Yamori, Takao,Tsuruo, Takashi
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p. 8215 - 8218
(2007/10/03)
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- A novel convenient route to the naturally occurring 3-oxoacyl-L-homoserinelactones and related bacterial autoinducers
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The naturally occurring 3-oxohexanoyl-L-homoserinelactone (1a), a bacterial autoinducer has been prepared in 47% overall yield by condensing stable 3-oxohexanoic acid (2), prepared by hydrolysis from the corresponding ester (3), with L-homoserinelactone using hydroxybenzotriazole (HOBT) and dicyclohexylcarbodiimide (DCC) in non-aqueous media.
- Dekhane, Mouloud,Douglas, Kenneth T.,Gilbert, Peter
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p. 1883 - 1884
(2007/10/03)
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- An Efficient Synthesis of Cobactin T, a Key Component of the Mycobactin Class of Siderophores
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Nα-Cbz-L-lysine t-butyl ester was oxidized by dimethyldioxirane to give nitrone 8c, which was converted to azopine derivative 15.Subsequent coupling and deprotection reactions afforded an efficient synthesis of cobactin T (19).
- Hu, Jingdan,Miller, Marvin J.
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p. 6379 - 6382
(2007/10/02)
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- Use of 1,3-dioxin-4-ones and related compounds in synthesis. 46. 2-(l-menthyloxycarbonyl)-2,6-dimethyl-1,3-dioxin-4-one and related compounds. Relationship between facial selectivity and pyramidalization
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Preparation and ground-state reactions (conjugate addition and catalytic hydrogenation) of a 1,3-dioxin-4-one having an l-menthyloxycarbonyl group at the 2-position as the only substituent (7a) and its 6-methyl derivative (8a), as well as their 2-methyl derivatives (5a and 6a), are reported. The X-ray structure of the 2-(methoxycarbonyl)-2-phenyl derivative (4b) was also determined. The result, when combined with previously reported X-ray crystallographic analyses on related dioxinones, suggests that all of the dioxinones take a sofa conformation of the six-membered ring, whose top face is always on the same side as the pyramidalization of the enone function in the ring. Conjugate addition reaction of Sa leads to exclusive addition on the bottom face, while addition to 7a gives the product corresponding to the top face addition. Catalytic hydrogenation of 6a and 8a is also reported. Though the selectivity is much lowered as compared with the conjugate addition, the same facial selectivities are again observed. A comparison with the exclusive top face attack on 2-tert-butyl-1,3-dioxin-4-one (1) and its 2-methyl derivative 2 and bottom face attack on 2-(l-menthyloxycarbonyl)-2-phenyl-1,3-dioxin-4-one (3a) makes it clear that the prediction of facial selectivity in these ground-state reactions (conjugate addition and catalytic hydrogenation) based on pyramidalization is not always correct. A novel hypothesis which accounts for all of the above results (sofa conformation of the hetero ring, pyramidalization at the enone portion, and facial selectivity) is presented.
- Sato, Masayuki,Murakami, Masayuki,Sunami, Satoshi,Kaneko, Chikara,Furuya, Toshio,Kurihara, Hiroyuki
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p. 4279 - 4287
(2007/10/02)
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- Preparation and structure of oligolides from (R)-3-hydroxypentanoic acid and comparison with the hydroxybutanoic-acid derivatives: A small change with large consequences
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Cyclic oligomers of (R)-3-hydroxyvaleric acid (3-HV) are prepared from the monomer by three different methods, giving various ratios of the oligomers. The macrocycles containing three to twelve 3-HV units (12- to 48-membered rings) are isolated in pure form by chromatography. The triolide 3 can be separated by distillation and isolated on large scale. Biopol, the copolymer of (R)-3-hydroxybutanoic acid (3-HB) and (R)-3-hydroxyvaleric acid (3-HV), is degraded to mixtures of Me- and Et-substituted triolides ('mixolides') with high crystallization tendency. The X-ray crystal structures of the tetrolide 4, pentolide 5, hexolide 6, heptolide 7, and of two 'mixolides' (with inclusions of solvent) have been determined and are compared with those of the corresponding 3-HB derivatives reported previously. From the structural data, a 31 and a 21 helix of 3-HV can be modelled, and the latter one compared with helix structures of P(3-HB) and P(3-HV) derived from stretch-fibre X-ray scattering. Crystals of a water-containing NaSCN complex of the triethyl triolide 3 were obtained in good quality for X-ray analysis. The structure contains an interesting array of C=O and H2O O-atoms around the Na+ ions along a channel-type tube (a-axis of the crystal) which may be relevant to the role of P(3-HB) and P(3-HV) as components of cellular ion channels.
- Seebach,Hoffmann,Kuhnle,Lengweiler
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p. 2007 - 2034
(2007/10/02)
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- Optically active substance and liquid crystal composition comprising same
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Disclosed is an optically active substance represented by the formula: STR1 wherein m is an integer of 1 to 14, Y is STR2 R is --Cn H2n+1, --OCn H2n+1, --OCOCn H2n+1 or --COOCn H2n+1 (in which n is an integer of 1 to 18), each of the asterisked carbon atoms is an asymmetric carbon atom, X a single bond, --CO2 --, or --OCO--, and A1 and A2 is hydrogen, fluorine, chlorine, bromine, cyano or methoxy.
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-
- Production of (S)-(+)-3-Hydroxybutyric Acid from 1,3-Butanediol by Resting Cells of Yeasts
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Various yeast strains were screened for production of 3-hydroxybutyric acid (3-HBA) from 1,3-butanediol (1,3-BD) by a resting cell system.Many yeasts were found to oxidize 1,3-BD to 3-HBA.Among them, Hansenula anomala IFO 0195 produced (S)-(+)-3-HBA of the highest optical purity and production of the acid.When resting cells of this strain were incubated at 27 deg C in an optimal reaction mixture containing 60.0 mg/ml 1,3-BD, 2.0percent CaCO3, and 1.0percent glucose, 26.7 mg/ml of 3-HBA were produced with 88percent enantiomer excess for 2 days.Dominant accumulation of (S)-(+)-3-HBA might be due to enantioselective degradation of (R)-(-)-3-HBA, though both (S)-(+)- and (R)-(-)-1,3-BD are oxidized by the strain.
- Shigeno, Toshiya,Katayama, Akiko,Nakahara, Tadaatsu
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p. 320 - 323
(2007/10/02)
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- New chiral phospholanes; synthesis, characterization, and use in asymmetric hydrogenation reactions
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We describe the practical synthesis of enantiomerically pure trans-2,5-disubstituted-1-phenylphospholanes which are then employed in the preparation of a new series of C2-symmetric bis- and C3-symmetric tris(phospholane) ligands. A versatile three-step route to the important chiral 1,4-diol intermediates, used in the phosphine syntheses, is outlined. Rhodium complexes bearing the new phosphine ligands were prepared and shown to act as efficient catalyst precursors for the enantioselective hydrogenation of various unsaturated substrates.
- Burk,Feaster,Harlow
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p. 569 - 592
(2007/12/18)
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- Asymmetric Reduction of Aliphatic Short- to Long-Chain β-Keto Acids by Use of Fermenting Bakers' Yeast
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Eleven β-keto acids, ranging from 3-oxobutanoic to 3-oxooctanoic acids, were reduced with fermenting bakers' yeast to the corresponding optically active β-hydroxy acids, which were isolated as the methyl esters.In all cases, the (R)-hydroxy acids were obtained in >/=98percent ee, except for 3-oxobutanoic acid, which afforded the (S)-hydroxy acid in 86percent ee.Inhibition of fermentation was observed for 3-oxoundecanoic to 3-oxotetradecanoic acids, leading to no reduction.Lowering of the substrate concentration was found to be appreciably effective in avoiding inhibition.
- Utaka, Masanori,Watabu, Hisashi,Higashi, Hiroshi,Sakai, Takashi,Tsuboi, Sadao,Torii, Sigeru
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p. 3917 - 3921
(2007/10/02)
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- Note on Biotransformations with Halobacterium halobium: Reduction of Ethyl 3-Oxobutanoate and Hydrolysis of Ethyl 3-Hydroxybutanoate. Cooperative Effects of Reductase and Hydrolase
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The archaebacterium Halobacterium halobium, growing in saturated NaCl solution, is tested for its ability to achieve biotransformations.We found that this microorganism does accept only a small veriety of compounds as substrates.Ethyl acetoacetate (1) is reduced to ethyl (S)-3-hydroxybutanoate (2) of optical purity of 40-76 percent, but in low chemical yields.The reduction is accompanied by hydrolysis of the hydroxy-ester to 3-hydroxybutanoic acid (3).Hydrolysis of rac-ester 2 by Halobacterium halobium gives (R)-2 of optical purity of up to 88 percent, depending upon reaction time, together with the almost racemic hydroxy-acid 3, both in low chemical yields.Hopes that the 'extremist' Halobacterium halobium would be able to effect unique conversions were not fulfilled.
- Ehrler, Juerg von,Seebach, Dieter
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p. 793 - 799
(2007/10/02)
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- Novel Ferroelectric Liquid Crystals Derived from Normal Alkyl Esters of (R)-3-Hydroxybutanoic Acid. The Correlation between Molecular Structure and Mesomorphic Properties
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The following series of novel ferroelectric liquid crystals, derived from normal alkyl esters of (R)-3-hydroxybutanoic acid, have been synthesized, and several factors determining their mesomorphic properties have been investigated I(m,n), II(m,n), III (10,3), IV(10,3).The smectic polymorphism for these compounds with three aromatic rings is strongly affected by the position and kind of the linkage groups in the core.The effects of the lengths of the two terminal chains (m,n) and the linkage groups in the core on the thermal stability of the smectic A and chiral smectic C phases have been discussed from the structural points of wiew.
- Nakauchi, Jun,Sakashita, Keiichi,Kageyama, Yoshitaka,Hayashi, Seiji,Mori, Kenji
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p. 1011 - 1016
(2007/10/02)
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- Einfache Umwandlung von (-)-(R)-3-Hydroxybuttersaeure in das (+)-(S)-Enantiomere und dessen Lacton (-)-(S)-4-Methyloxethan-2-on
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Condensation of (R)-3-hydroxybutanoic acid (1) with ethyl orthoacetate gives a 2-ethoxy-substituted 1,3-dioxanone 2 which is thermally labile: at ca. 100 deg C, two competing processes commence, one leading to ethyl (R)-3-acetoxybutanoate (3), the other one - with complete inversion of configuration - to the (S)-4-methyloxetan-2-one (4) and ethyl acetate.These can be readily separated by fractional distillation.Thus, enantiomerically pure (S)-3-hydroxybutanoic acid (ent-1) and l-2-alkyl-3-hydroxybutanoic acid derivatives (such as 6 and 8) become available from the biopolymer PHB, the precursor to the acid 1.
- Griesbeck, Axel,Seebach, Dieter
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p. 1320 - 1325
(2007/10/02)
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- PHOTOCYCLOADDITION, METHYLATION, AND CATALYTIC REDUCTION OF CHIRAL SPIROCYCLIC 1,3-DIOXIN-4-ONES: DIFFERENT STEREOFACIAL SELECTIVITY AND ITS EXPLANATION
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We describe several reactions of chiral spirocyclic 1,3-dioxinones, all of which proceed in high stereofacial selectivity.A possible reason for the different selectivities in these reactions is proposed.KEYWORDS - asymmetric photocycloaddition; spirocyclic 1,3-dioxin-4-one; stereofacial differentation; crystal stucture; (R)-3-hydroxybutyric acid; 1-menthone; chiral auxiliary group
- Sato, Masayuki,Takayama, Kazuhisa,Furuya, Toshio,Inukai, Noriyoshi,Kaneko, Chikara
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p. 3971 - 3974
(2007/10/02)
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- Photosensitized NAD(P)H Regeneration Systems; Application in the Reduction of Butan-2-one, Pyruvic, and Acetoacetic Acids and in the Reductive Amination of Pyruvic and Oxoglutaric Acid to Amino Acid
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The photosensitized formation of NAD(P)H by enzyme-catalysed processes has been accomplished.With Ru(bpy)32+ as sensitizer, methyl viologen, MV2+ as primary electron acceptor, and (NH4)3EDTA or 2- mercaptoethanol, NADPH is formed in the presence of ferredoxin NADP+-reductase as enzyme catalyst.Zinc(II)meso-tetramethylpyridiniumporphyrin, ZnTMPy4+ is used as sensitizer for the photoinduced production of NADH using the same components and lipoamide dehydrogenase as enzyme catalyst.The photoinduced NAD(P)H regeneration systems have been coupled to secondary enzyme-catalysed processes such as the reduction of butan-2-one to butan-2-ol, pyruvic acid to lactic acid, acetoacetic acid to β-hydroxybutyric acid, as well as to the reductive amination of pyruvic acid to alanine and of α-oxoglutaric acid to glutamine acid.The products exhibit high optical purity and the enzymes and the coenzymes show high turnover numbers and stability.
- Mandler, Daniel,Willner, Itamar
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p. 805 - 812
(2007/10/02)
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- Chirale Synthesebausteine durch Kolbe-Elektrolyse enantiomerenreiner β-Hydroxy-carbonsaeurederivate, (R)- und (S)-Methyl- sowie (R)-Trifluormethyl-γ-butyrolactone und δ-valerolactone
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The coupling of chiral, non-racemic R* groups by Kolbe electrolysis of carboxylic acids R*COOH is used to prepare compounds with a 1,4- and 1,5-distance of the functional groups.The suitably protected β-hydroxycarboxylic acids (R)- or (S)-3-hydroxybutyric acid, (R)-4,4,4-trifluoro-3-hydroxybutyric acid (as acetates; see 1-6), and (S)-malic acid (as (2S,5S)-2-(tert-butyl)-5-oxo-1,3-dioxolan-4-acetic acid, see 7) are decarboxylatively dimerized or "codimerized" with 2-methylpropanoic acid, with 4-(formylamino)butyric acid, and with monomethyl malonate and succinate.The products formed are derivatives of (R,R)-1,1,1,6,6,6-hexafluoro-2,5-hexanediol (see 8), of (R)-5,5,5-trifluoro-4-hydroxypentanoic acid (see 9, 10), of (R)- and (S)-5-hydroxyhexanoic acid (see 11) and its trifluoro analogue (see 12, 13), of (S)-2-hydroxy- and (S,S)-2,5-dihydroxyadipic acid (see 23, 20), of (S)-2-hydroxy-4-methylpentanoic acid ("OH-leucine", see 21), and of (S)-2-hydroxy-6-aminohexanoic acid ("OH-lysine", see 22).Some of these products are further converted to CH3- or CF3-substituted γ- and δ- lactones of (R)- or (S)-confuguration (14, 16-19), or to an enantiomerically pure derivative of (R)-1-hydroxy-2-oxocyclopentane-1-carboxylic acid (see 24).Possible uses of these new chiral building blocks for the synthesis of natural products and their CF3 analogues (brefeldin, sulcatol, zearalenone) are discussed.The olfactory properties of (R)- and (S)-δ-caprolactone (18) are compared with those of (R)-6,6,6-trifluoro-δ-caprolactone (19).
- Seebach, Dieter,Renaud, Philippe
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p. 2342 - 2349
(2007/10/02)
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- Ueber die Depolymerisierung von Poly-(R)-3-hydroxy-buttersaeureester (PHB)
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On the Depolimerization of Poly-(R)-3-hydroxy-butanoate (PHB): From cell-free PHB or from dried cells of Alcaligens eutrophus H 16, which had been grown in an aqueous fructose solution, enantiomerically pure methyl, ethyl, butyl or β-methoxyethyl (R)-3-hydroxy-butanoates are obtained in yields ranging from 75-90percent (0.1 to 70 g scale).The depolimerization is achieved by heating the PHB-containing materials to temperatures of 80-100 deg C in the corresponding alcohol with or without the cosolvent dichloroethane in the presence of either sulfuric acid or tetraethoxytitanium catalyst.Since (S)-3-hydroxy-butanoates are also readily obtained (by yeast reduction of aceto-acetates), starting materials derived from 3-hydroxy-butyric acid now belong to the especially useful group of synthetic building blocks which are available in both enantiomeric forms.
- Seebach, Dieter,Zueger, Max
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p. 495 - 503
(2007/10/02)
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- Mycobactins: Synthesis of (-)-Cobactin T from ε-Hydroxynorleucine
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The synthesis of (-)-cobactin T is described, the key step being ring closure between C6 and the hydroxamate N of α-N-(tert-butoxycarbonyl)-ε-hydroxynorleucine O-benzylhydroxamate.
- Maurer, Peter J.,Miller, Marvin J.
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p. 2835 - 2836
(2007/10/02)
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