- Sesquiterpene dimers esterified with diverse small organic acids from the seeds of Sarcandra glabra
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11 new sesquiterpene dimers, sarglabolides A-K (1-11), and five known ones were isolated from the seeds of Sarcandra glabra. Their structures were elucidated by spectroscopic data analysis and chemical evidence. Sarglabolide A (1) was verified to exclusively possess a seventeen-membered macrocyclic ester ring formed by the scaffold of the sesquiterpene dimer and small organic acids, different from the eighteen-membered rings of the other reported analogues. The chiral small organic acid moieties were assigned to l-malic acid, d-malic acid, and d-tartaric acid based on the combination of spectroscopy, chemical derivatization and HPLC analysis. Dimers 1, 12 and 13 can significantly inhibit NO production in LPS-induced macrophages with IC50 values at 3.04, 4.65 and 2.33 μmol/L, respectively.
- Wang, Peng,Luo, Jun,Zhang, Yang-Mei,Kong, Ling-Yi
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p. 5362 - 5370
(2015/07/15)
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- An approach to the chemotaxonomic differentiation of two European Dog's mercury species: Mercurialis annua L. and M. perennis L.
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Mercurialis annua and M. perennis are medicinal plants used in complementary medicine. In the present work, analytical methods to allow a chemotaxonomic differentiation of M. annua and M. perennis by means of chemical marker compounds were established. In addition to previously published compounds, the exclusive presence of pyridine-3-carbonitrile and nicotinamide in CH2Cl2 extracts obtained from the herbal parts of M. annua was demonstrated by GC/MS. Notably, pyridine-3-carbonitrile was identified for the first time as a natural product. Further chromatographic separation of the CH2Cl2 extracts via polyamide yielded a MeOH fraction exhibiting a broad spectrum of side-chain saturated n-alkylresorcinols. While the n-alkylresorcinol pattern was similar for both plant species, some specific differences were observed for particular n-alkylresorcinol homologs. Finally, the investigation of H2O extracts by LC/MS/MS revealed the presence of depside constituents. Whereas, in M. perennis, a mixture of mercurialis acid (=(2R)-[(E)-caffeoyl]-2-oxoglutarate) and phaselic acid (=(E)-caffeoyl-2-malate) could be detected, in M. annua solely phaselic acid was found. By comparison with synthesized enantiomerically pure (2R)- and (2S)-phaselic acids, the configuration of the depside could be determined as (2S) in M. annua and as (2R) in M. perennis.
- Lorenz, Peter,Duckstein, Sarina,Conrad, Juergen,Knoedler, Matthias,Meyer, Ulrich,Stintzing, Florian C.
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experimental part
p. 282 - 297
(2012/05/04)
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- METHODS OF PREPARATION OF MACROCYCLIC COMPOUNDS
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The instant invention describes methods for producing macrocyclic compounds having antiproliferation activity, and useful in methods of treating disorders such as cancer, tumors and cell proliferation related disorders.
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Page/Page column 24-25
(2009/10/18)
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- Reverse reaction of malic enzyme for HCO3- fixation into pyruvic acid to synthesize L-malic acid with enzymatic coenzyme regeneration
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Malic enzyme [L-malate: NAD(P)+ oxidoreductase (EC 1.1.1.39)] catalyzes the oxidative decarboxylation of L-malic acid to produce pyruvic acid using the oxidized form of NAD(P) (NAD(P)+). We used a reverse reaction of the malic enzyme of Pseudomonas diminuta IFO 13182 for HCO 3- fixation into pyruvic acid to produce L-malic acid with coenzyme (NADH) generation. Glucose-6-phosphate dehydrogenase (EC1.1.1.49) of Leuconostoc mesenteroides was suitable for coenzyme regeneration. Optimum conditions for the carboxylation of pyruvic acid were examined, including pyruvic acid, NAD+, and both malic enzyme and glucose-6-phosphate dehydrogenase concentrations. Under optimal conditions, the ratio of HCO 3- and pyruvic acid to malic acid was about 38% after 24 h of incubation at 30°C, and the concentration of the accumulated L-malic acid in the reaction mixture was 38mM. The malic enzyme reverse reaction was also carried out by the conjugated redox enzyme reaction with water-soluble polymer-bound NAD1.
- Ohno, Yoko,Nakamori, Toshihiko,Zheng, Haitao,Suye, Shin-Ichiro
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p. 1278 - 1282
(2008/12/21)
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- Purification and characterization of fumarase from Corynebacterium glutamicum
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Fumarase (EC 4.2.1.2) from Corynebacterium glutamicum (Brevibacterium flavum) ATCC 14067 was purified to homogeneity. Its amino-terminal sequence (residues 1 to 30) corresponded to the sequence (residues 6 to 35) of the deduced product of the fumarase gene of C. glutamicum (GenBank accession no. BAB98403). The molecular mass of the native enzyme was 200 kDa. The protein was a homotetramer, with a 50-kDa subunit molecular mass. The homotetrameric and stable properties indicated that the enzyme belongs to a family of Class II fumarase. Equilibrium constants (Keq) for the enzyme reaction were determined at pH 6.0, 7.0, and 8.0, resulting in Keq = 6.4, 6.1, and 4.6 respectively in phosphate buffer and in 16, 19, and 17 in non-phosphate buffers. Among the amino acids and nucleotides tested, ATP inhibited the enzyme competitively, or in mixed-type, depending on the buffer. Substrate analogs, meso-tartrate, D-tartrate, and pyromellitate, inhibited the enzyme competitively, and D-malate in mixed-type.
- Genda, Tomoko,Watabe, Shoji,Ozaki, Hachiro
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p. 1102 - 1109
(2008/02/10)
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- Method for purifying succinic acid from fermentation broth
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Succinic acid is produced by bringing a succinic acid-containing liquid containing succinic acid and cation which is obtained by fermentation or an enzymatic method into contact with an H-type strongly acidic cation-exchange resin in an amount equivalent to or more than the amount of cation other than hydrogen ion contained in the succinic acid-containing liquid, and precipitating a crystal of succinic acid from the obtained ion-exchange-treated liquid to obtain purified succinic acid.
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Page/Page column 9
(2008/06/13)
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- New results on the stereoselective alkylations of malic acid derivatives supported by molecular modeling
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The stereoselectivity of the alkylation of dialkyl malates is dependent on steric hindrance of both ester alkyl groups. It was found that the two alkyl groups have opposite effects on diastereoselectivity. Increased steric hindrance at the C(1) carboxy group increases the anti-selectivity, whereas increased steric hindrance at the C(4) carboxy group decreases it. The results are explained by comparing the structures of the enolates, which were obtained by molecular modeling. Alkylation at C(4′) of dioxolanones, derived from benzyl-substituted malic acids, with an additional stereogenic center on the side chain is dependent on the stereogenic centers of the ring acetal and of the side chain. Alkylation at low temperatures occurs only with cis-dioxolanones having an (R)-configured side-chain stereogenic center. The corresponding trans-dioxolanone and the cis-dioxolanone with a (S)-configured side-chain stereogenic center were recovered unchanged. A rationale is presented with models of monolithiated dioxolanones obtained by ab initio calculations.
- Sefkow, Michael,Koch, Andreas,Kleinpeter, Erich
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p. 4216 - 4229
(2007/10/03)
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- New phenolic constituents from the fruit juice of Phyllanthus emblica
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Six new phenolic constituents, L-malic acid 2-O- (1), mucic acid 2-O- (5), mucic acid 1,4-1actone 2-0- (6), 50- (8), 3-0- (10), and 3,5-di-0- (11) gallates, were isolated from the fruit juice of Phyllanthus emblica together with their methyl esters (2-4,
- Zhang,Tanaka,Yang,Kouno
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p. 537 - 540
(2007/10/03)
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- 13C, 15N, and 18O equilibrium isotope effects and fractionation factors
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A listing of 13C, 15N, and 18O equilibrium isotope effects and fractionation factors for atoms in specific positions is provided. Empirical factors that can be used to adjust these fractionation factors for more complex structures are presented and discussed. While much work needs to be done to determine equilibrium isotope effects for these heavy atoms, the values tabulated here should be useful to anyone working with isotope effects involving these atoms.
- Rishavy, Mark A.,Cleland
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p. 967 - 977
(2007/10/03)
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- 1,5-Asymmetric inductions in the reactions of 2-(2',3',4',6'-tetra-O-acetyl-β-D-glucopyranosyloxy)benzaldehyde with Danishefsky's diene
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The title compounds react to give mainly a 9:1 mixture of the aldols 14 and 15 in THF in the presence of BF3.OEt2, a 6:1 mixture of the cycloadducts 16 and 17 in THF in the presence of ZnCl2, and a 1:3 mixture of the cycloadducts 16 and 17 in toluene in the presence of Eu(fod)3.
- Cousins,Curtis,Ding,Stoodley
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p. 8689 - 8692
(2007/10/02)
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- Preparation of Both Enantiomers of Malic and Citramalic Acid and Other Hydroxysuccinic Acid Derivatives by Stereospecific Hydrations of cis or trans 2-Butene-1,4-dioic Acids with Resting Cells of Clostridium formicoaceticum
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(R)-Malic, (S)-malic, (R)-citramalic, (S)-citramalic, (2R,3S)-2-hydroxy-3-methylsuccinic and (2R,3S)-2,3-dimethyl-2-hydroxysuccinic acid were prepared on scales up to 25 mmol by stereospecific addition of water to different 2-butene-1,4-dioic acid derivatives catalyzed by resting cells of Clostridium formicoaceticum (Scheme 1).The (3R)-monodeuterio (R)- and (S)-malic acid as well as (R)- and (S)-citramalic acid were prepared using freeze-dried cells in 2H2O-buffer.The stereochemical purity of the products was in most cases >/= 99percent.
- Eck, Richard,Simon, Helmut
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p. 13641 - 13654
(2007/10/02)
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- Total synthesis of natural (+)-ambruticin
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The structurally unique antifungal antibiotic ambruticin (1) has been prepared for the first time in a convergent synthesis. The strategy for its synthesis involved the independent preparation of the enantiomerically pure fragments 19, 31 and 49. The required C(7) - C(8) β-C-glycoside bond was formed by coupling the glycosyl fluoride 19 with the in situ formed vinyl alane derivative 32. Formation of the C(13) - C(14) trans double bond was accomplished by condensation of the sulfone fragment 49 with the aldehyde intermediate 35 leading to the complete skeletal framework of ambruticin. Saponification of 51 and then cleavage of the benzyl protecting groups gave natural ambruticin.
- Kende, Andrew S.,Mendoza, Jose S.,Fujii, Yasuhiro
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p. 8015 - 8038
(2007/10/02)
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- On the factors controlling the structural specificity and stereospecificity of the L-lactate dehydrogenase from Bacillus stearothermophilus: Effects of Gln102→Arg and Arg171→Trp/Tyr double mutations
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The factors determining the L-stereospecificity of the L-lactate dehydrogenase from Bacillus stearolhermophilus have been probed by introducing Arg171Trp/Tyr and Gln 102Arg mutations. These changes preclude normal 2-keto acid substrate binding via an Arg171-COO- electrostatic interaction and are positioned to induce a reversal of the natural substrate binding mode, thereby leading to D-2-hydroxy acid formation. However, the L-stereospecificities of the mutant enzymes remain unchanged, showing that there are important fail-safe stereospecificity determinants that take over when the key Arg171-COO- binding interaction is removed. The effects of the mutations on structural specificity are approximately additive, resulting in the broad 2-keto acid specificity of the wild-type enzyme being changed to give catalysts highly selective for the dicarboxylic substrate oxalacetate.
- Kallwass, Helmut K.W.,Hogan, James K.,Macfarlane, Emma L.A.,Martichonok, Valeri,Partis, Wendy,Kay, Cyril M.,Gold, Marvin,Bryan Jones
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p. 10704 - 10710
(2007/10/02)
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- DESIGN OF CONTINUOUS FLOW IMMOBILIZED BACTERIAL CELLS REACTOR FOR PRODUCTION OF L-MALIC ACID
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An experimental study was carried out, aimed at establishing an engineering data base for the optimum design of a pilot-plant fixed bed reactor for continuous biotransformation of natrium fumarate to L-malic acid catalysed by immobilized bacterial cells.Cells Corynebacterium sp. immobilized in calcium alginate were used for experiments.Effective reaction kinetics including the effect of transport phenomena in the bed was determined and conditions of the safe conversion data scale up were defined.Regarding the requirements of continuous production, long-term stability of the biocatalytic system was tested at operation conditions corresponding to constant degree of substrate conversion at the reactor outlet.Quantitative evidence on changes of the effective reaction kinetics (i.e. on the decrease of the effective rate constant value) over the three-months production period as obtained from this experimental run.Decisive design parameters of a pilot-plant reactor were calculated for estimated production of 20 t of L-malic acid per 90 days period (maximum time of economic biocatalyst utilization).
- Fialova, Marie,Zahradnik, Jindrich,Kucerova, Hana
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p. 2192 - 2198
(2007/10/02)
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- Reactivite du nitrite de sodium. V. Action sur les amino-acides, peptides et proteines
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The action of sodium nitrite on various amino-acids was re-examined in conditions approximating to a biological medium. 13C-NMR provides evidence of the existence of intramolecular ring closures and the formation of 5-membered rings with ornithine, citrulline and arginine.The reaction of cystine shows the opening of the sulphur bridges, whereas cysteine leads to the formation of carboxy-thiiran and 3-sulpho-lactic acid.The hydrolysis of the amide bonds of asparagine and glutamine is complete whereas the peptides studied - carnosine and aspartam - do not undergo hydrolysis of the peptide linkage.However, the first deamination of glutathion (γ-Glu-Cys-Gly) induces the peptide link to be broken and a cyclization with the formation of lactone to occur.A second deamination takes place on the cysteinyl residue released and allows the formation of a thiiran by intramolecular cyclization with the thiol group.The formation of thiiran was also observed with oxidized glutathion which has an S-S bridge.Finally, the formation of nitrosamines was detected by 15N-NMR during the reaction of sodium nitrite with two commercial products available to the general public.
- Gouesnard, Jean-Paul
-
-
- Racemic Structure and Optical Resolution by Preferential Crystallization of (+/-)-Organic Ammonium Hydrogen Malates
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Gibbs energies of formation of racemate, binary melting point diagrams, and ternary solubility diagrams indicate that (+/-)-propylammonium ((+/-)-PA salt) and (+/-)-1,1,3,3-tetramethylbutylammonium ((+/-)-TMB salt) hydrogen malates are conglomerates at room temperature, whereas (+/-)-TMB salt forms a racemic compound at its melting point.Free energies of critical nucleation in supersaturated solutions were examined to resolve (+/-)-PA and -TMB salts efficiently by preferential crystallization.Successive preferential crystallization of (+/-)-PA salt in methanol at 10 deg C and that of (+/-)-TMB salt in water give (+)- and (-)-PA and -TMB salts with about 90percent optical purity.Optically pure (+)- and (-)-malic acids are obtained from purified (-)- and (+)-salts.
- Shiraiwa, Tadashi,Sado, Yujin,Inoue, Mitsuo,Sakamoto, Keiji,Miyazaki, Hideya,Kurokawa, Hidemoto
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p. 899 - 904
(2007/10/02)
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- PRODUCTION OF L-MALIC ACID BY IMMOBILIZED BACTERIAL CELLS OF THE GENUS Brevibacterium
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A HPLC procedure was developed permitting an exact rapid determination of L-malate, fumarate, succinate, and other dicarboxylic acids.The method was used to assay the products of fumarate metabolism in two Brevibacterium strains, obtained by screening, and showing a high fumarate conversion both in the cell suspension and in the immobilized system.Polyacrylamide and Ca-alginate were employed as polymeric matrices.The conditions were determined (pH, temperature, ion concentration, effect of inhibitors and detergents) under which L-malate is predominantly formed from fumarate and the conversion degree is the highest (8.60 mmol of L-malate h/g cells).The dependence of the conversion of various types of the polymeric matrix and the stability of the system in a continuous experimental arrangement were also examined.The results of these experiments will be utilized in L-malate technology.
- Cerny, Jaroslav,Skoda, Jan
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p. 1361 - 1372
(2007/10/02)
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- The Absolute Configuration of 4-(Trichloromethyl)oxetan-2-one; A Case of Double Anchimeric Assistance with Inversion
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It has been shown that the absolute configuration of the oxetan-2-one (1) is opposite to that of its hydrolysis product, S-(-)-malic acid (3).
- Wynberg, Hans,Staring, Emiel G. J.
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p. 1181 - 1182
(2007/10/02)
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- AMINO-ACIDS AS CHIRAL SYNTHONS : SYNTHESIS OF ENANTIOMERICALLY PURE α-HYDROXY ESTERS.
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Reaction of lithium homocuprates with α-hydroxy β-bromo ester derivated from aspartic acid affords α-hydroxy esters of high enantiomerical purity.
- Larcheveque, Marc,Petit, Yves
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p. 3705 - 3706
(2007/10/02)
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- Absolute Configuration of 4-Hydroxy-4-methylglutamic Acids
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The absolute configurations of the naturally occuring (2S,4S)-4-hydroxy-4-methylglutamic acid and (2S,4R)-4-hydroxy-4-methylglutamic acid have been determined.L-Amino acid oxidase was used in the determination of the (2S)-configuration of the amino acids.The diastereomeric (2S)-4-hydroxy-4-methylglutamic acids were transformed into (S)(+)-citramalic acid (R)(-)-citramalic acid, respectively, by oxidative deamination and decarboxylation using calcium hypochlorite.On the basis of the obtained results and the known absolute configuration of the enantiomeric citramalic acids, it was deduced that the configuration previously assigned the title compounds had to be changed.The structure of (2S,4S)-4-hydroxyglutamic acid has also been established by use of this method.The L-malic acid liberated was determined by its optical rotation and enzymatically by L-malic acid dehydrogenase.
- Bjerg, Birthe,Olsen, Ole,Sorensen, Hilmer
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p. 321 - 324
(2007/10/02)
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- The Co-immobilization of NAD and Dehydrogenases and Its Application to Bioreactors for Synthesis and Analysis
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A polymerizable NAD derivative, N6-carbamoylmethyl>-NAD, formate dehydrogenase, and malate dehydrogenase were entrapped all together in polyacrylamide gels.The entrapment was carried out by radical copolymerization, and consequently NAD was bound on the matrix which enclosed the enzymes.These gels had the function of producing L-malate from oxalacetate and formate.The L-malate production was also continuously done in a column reactor for 3 days.Another gel was similarly preparated with N6--NAD, horse liver alcohol dehydrogenase, and diaphorase.This gel was shown to catalyze the formation of resorufin from resazurin and ethanol.This gel was applicable to ethanol analysis using a fluorescence spectrophotometer to determine resorufin.The analyzer was usable for one week.
- Yamazaki, Yoshimitsu,Maeda, Hidekatsu
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p. 1571 - 1582
(2007/10/02)
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- A NOVEL ACYLPHLOROGLUCINOL FROM THE BROWN ALGA ZONARIA TOURNEFORTII
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A novel acylphloroglucinol, (5Z,8Z,11Z,13E,17Z)-2'-eicosa-15(S)-hydroxy-5,8,11,13,17-pentaenoylphloroglucinol, has been isolated from the brown alga Zonaria tournefortii and its structure proved by spectroscopic and chemical methods.Key Word Index - Zonaria tournefortii; Dictyotaceae; brown algae; phloroglucinol derivative; (5Z,8Z,11Z,13E,17Z)-2'-eicosa-15(S)-hydroxy-5,8,11,13,17-pentaenoylphloroglucinol.
- Amico, Vincenzo,Nicolosi, Giovanni,Oriente, Giovanna,Piattelli, Mario,Tringali, Corrado
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p. 739 - 742
(2007/10/02)
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- Asymmetric Synthesis of (S)- and (R)-Malic Acid from Ketene and Chloral
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Quinidine (5) catalyzes the addition of ketene (1) to chloral (2) at -50 deg C in toluene.The β-(trichloromethyl)-β-propiolactone 3 is formed virtually optically pure (98percent enantiomeric excess).A mechanism for this reaction, accounting for the high enantiomeric excess, is proposed.Known hydrolytic procedures convert the lactone 3 to malic acid (6).By proper choice of catalyst both (R)- and (S)-malic acid can be obtained optically pure.
- Wynberg, Hans,Staring, Emiel G. J.
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p. 166 - 168
(2007/10/02)
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