scholarly journals Benzyl (R)-2-(Acetylthio)Propanoate: A Promising Sulfur Isoster of (R)-Lactic Acid and Ester Precursors

Molbank ◽  
10.3390/m1010 ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. M1010
Author(s):  
Ryosuke Sasaki ◽  
Momoyo Kawamoto ◽  
Yoo Tanabe
Keyword(s):  
Lactic Acid ◽  
Column Chromatography ◽  
Hplc Analysis ◽  
Enantiomeric Excess ◽  
Propanoic Acid ◽  
Displacement Reaction ◽  
Acetyl Group ◽  
Benzyl Esters ◽  
Sulfur Containing

In this paper, an accessible chiral pool synthesis of benzyl (R)-2-(acetylthio)propanoate (acetylthiolactate), which is less odorous than the methyl or ethyl analogue, was performed through a clean SN2 displacement reaction using available AcSK with tris[2-(2-methoxyethoxy)]ethylamine (TDA-1), starting from commercially available benzyl (S)-lactate in 76%, 94% ee (2 steps). Deprotection of the acetyl group using N,N-dimethylethylenediamine afforded benzyl (R)-2-sulfanylpropanoate in 93% yield with 90% ee. These two sulfur-containing benzyl esters were sufficiently odorless to be purified by column chromatography. Direct HPLC analysis was applied to determine the enantiomeric excess without thiazolidin-4-one derivatizations. A complementary debenzylation of benzyl (R)-2-(acetylthio)propanoate was also performed using HBr/AcOH to afford (R)-2-(acetylthio)propanoic acid without critical racemization in 92% yield with 92% ee.

Column chromatography of some sulfur-containing amino acids

1965 ◽  
Vol 18 ◽  
pp. 492-497 ◽  
Author(s):  
C. De Marco ◽  
R. Mosti ◽  
D. Cavallini
Keyword(s):  
Amino Acids ◽  
Column Chromatography ◽  
Sulfur Containing

scholarly journals Capnophilic Lactic Fermentation from Thermotoga neapolitana: A Resourceful Pathway to Obtain Almost Enantiopure L-lactic Acid

Fermentation ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 34 ◽  
Author(s):  
Genoveffa Nuzzo ◽  
Simone Landi ◽  
Nunzia Esercizio ◽  
Emiliano Manzo ◽  
Angelo Fontana ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Enantiomeric Excess ◽  
Thermophilic Bacterium ◽  
Racemic Mixture ◽  
Thermotoga Neapolitana ◽  
High Concentration ◽  
Lactic Fermentation ◽  
Bacterial Fermentation ◽  
First Time

The industrial production of lactic acid (LA) is mainly based on bacterial fermentation. This process can result in enantiopure or racemic mixture according to the producing organism. Between the enantiomers, L-lactic acid shows superior market value. Recently, we reported a novel anaplerotic pathway called capnophilic lactic fermentation (CLF) that produces a high concentration of LA by fermentation of sugar in the anaerobic thermophilic bacterium Thermotoga neapolitana. The aim of this work was the identification of the enantiomeric characterization of the LA produced by T. neapolitana and identification of the lactate dehydrogenase in T. neapolitana (TnLDH) and related bacteria of the order Thermotogales. Chemical derivatization and GC/MS analysis were applied to define the stereochemistry of LA from T. neapolitana. A bioinformatics study on TnLDH was carried out for the characterization of the enzyme. Chemical analysis showed a 95.2% enantiomeric excess of L-LA produced by T. neapolitana. A phylogenetic approach clearly clustered the TnLDH together with the L-LDH from lactic acid bacteria. We report for the first time that T. neapolitana is able to produce almost enantiopure L-lactic acid. The result was confirmed by bioinformatics analysis on TnLDH, which is a member of the L-LDH sub-family.

Un nouvel agent de glycosylation: l'anhydride trifluorométhanesulfonique. Synthèse des α et β O-glycosyl-L-sérine, -L-thréonine et -L-hydroxyproline

1981 ◽  
Vol 59 (2) ◽  
pp. 473-481 ◽  
Author(s):  
J. M. Lacombe ◽  
A. A. Pavia ◽  
J. M. Rocheville
Keyword(s):  
Column Chromatography ◽  
Optical Rotation ◽  
Benzyl Ester ◽  
Experimental Procedure ◽  
Condensation Products ◽  
Benzyl Esters ◽  
Similar Yield ◽  
C Nmr

When 2,3,4,6-tetra-O-benzyl-D-glucopyranose, -D-galactopyranose and 2,3,4-tri-O-benzyl-D-xylopyranose were allowed to react in the cold in dichloromethane or acetonitrile as solvent in the presence of trifluoromethanesulfonic (triflic) anhydride, with methyl or benzyl esters of the N-(benzyloxycarbonyl)-L-serine, -L-threonine, and -L-hydroxyproline, an anomeric mixture of the corresponding O-glycosylaminoacids was obtained (55 to 90% overall yield), with the α-anomer being predominant. The same experimental procedure was successfully applied to the condensation of the benzyl ester of the N-(benzyloxycarbonyl)-L-hydroxyproline with 2,3,4-tri-O-benzyl-L-arabinopyranose and 2,3,5-tri-O-benzyl-L-arabinofuranose affording the corresponding condensation products with similar yield. Pure α and β anomers were obtained after column chromatography or crystallization with 30 to 65% yield. Hydrogenolysis of benzyl derivatives afforded the unprotected compounds. Optical rotation, 1H and 13C nmr were the main methods used to assess structure and stereochemistry.

THE METABOLISM OF 2-KETO-D-GLUCONATE BY RESTING CELLS OF LEUCONOSTOC MESENTEROIDES

1960 ◽  
Vol 6 (1) ◽  
pp. 107-114
Author(s):  
E. R. Blakley ◽  
A. C. Blackwood
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Column Chromatography ◽  
Leuconostoc Mesenteroides ◽  
Fermentation Medium ◽  
Resting Cells

The rate of utilization of 2-keto-D-gluconate and the accumulation of pentulose by resting cells of Leuconostoc mesenteroides is affected markedly by pH, Below pH 5, 2-keto-D-gluconate is utilized slowly and pentulose accumulates in the fermentation medium. The pentulose was separated by column chromatography and identified as D-xylulose and D-ribulose. The products of the fermentation of 2-keto-D-gluconate by resting cells, in addition to pentulose, are carbon dioxide, acetic acid, and lactic acid, as expected from the studies with growing cultures. The results obtained are unexpected when considered with what is known about the metabolism of 2-keto-D-gluconate by this organism.

Global versus local adsorption selectivity

2015 ◽  
Vol 14 (4) ◽  
pp. 563-570 ◽  
Author(s):  
Françoise Pauzat ◽  
Gael Marloie ◽  
Alexis Markovits ◽  
Yves Ellinger
Keyword(s):  
Lactic Acid ◽  
Density Functional ◽  
Selective Adsorption ◽  
Enantiomeric Excess ◽  
Local Property ◽  
Adsorption Selectivity ◽  
Adsorption Sites ◽  
Simulation Techniques ◽  
Adsorption Processes ◽  
Property Changes

AbstractThe origin of the enantiomeric excess found in the amino acids present in the organic matter of carbonaceous meteorites is still unclear. Selective adsorption of one of the two enantiomers existing after a racemic formation could be part of the answer. Hereafter we report a comparative study of the adsorption of the R and S enantiomers of α-alanine and lactic acid on the hydroxylated {$10\bar 10$} chiral surface of α-quartz using numerical simulation techniques. Structurally different adsorption sites were found with opposite R versus S selectivity for the same molecule–surface couple, raising the problem of whether to consider adsorption as a local property or as a global response characteristic of the whole surface. To deal with the second term of this alternative, a statistical approach was designed, based on the occurrence of each adsorption site whose energy was calculated using first principle periodic density functional theory. It was found that R-alanine and S-lactic acid are the enantiomers preferentially adsorbed, even if the adsorption process on the quartz {$10\bar 10$} surface stays with a disappointingly poor enantio-selectivity. Nevertheless, it highlighted the important point that considering adsorption as a global property changes perspectives in the search for more efficient enantio-selective supports and more generally changes the way to apprehend adsorption processes in astro-chemistry/biology.

scholarly journals Chiroptical activity of hydroxycarboxylic acids: implications for the origin of biological homochirality

2021 ◽  
Author(s):  
Jana Bocková ◽  
Nykola Jones ◽  
Uwe Meierhenrich ◽  
Søren Hoffmann ◽  
Cornelia Meinert
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Enantiomeric Excess ◽  
Building Blocks ◽  
Aliphatic Chain ◽  
Monocarboxylic Acids ◽  
Hydroxycarboxylic Acids ◽  
Polarised Light ◽  
Suitable Target ◽  
Anisotropy Spectra

Abstract Circularly polarised light (CPL) interacting with interstellar organic molecules might have imparted chiral bias and hence preluded prebiotic evolution of biomolecular homochirality. The l-enrichment of extra-terrestrial amino acids in meteorites, as opposed to no detectable excess in monocarboxylic acids and amines, has previously been attributed to their intrinsic interaction with stellar CPL revealed by substantial differences in their chiroptical signals. Recent analyses of meteoritic hydroxycarboxylic acids (HCAs) – potential co-building blocks of ancestral proto-peptides – showed an enantiomeric excess in l-lactic acid. Here we report on novel anisotropy spectra of several HCAs using a synchrotron radiation electronic circular dichroism spectrophotometer to support the re-evaluation of chiral biomarkers of extra-terrestrial origin in the context of absolute photochirogenesis. We found that irradiation by CPL which would yield l-excess in amino acids would also yield lexcess in aliphatic chain HCAs including lactic acid as well as mandelic acid in the examined conditions. Only tartaric acid would show “unnatural” d-enrichment, which makes it a suitable target compound for further assessing the relevance of the CPL scenario.

scholarly journals CHARACTERIZATION OF TETRAGENOCOCCUS HALOPHILUS FROM VIETNAMESE FISH SAUCE

2019 ◽  
Vol 57 (5) ◽  
pp. 544
Author(s):  
Le Thanh Ha ◽  
Nguyen Nam Trinh ◽  
Le Thi My Chau ◽  
Nguyen Thi Minh Tu
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Volatile Compounds ◽  
Volatile Compound ◽  
Fish Sauce ◽  
Tetragenococcus Halophilus ◽  
Halophilic Lactic Acid Bacteria ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

The intracellular aminopeptidase activities and volatile compound profile of isolated halophilic lactic acid bacteria Tetragenococcus halophilus was investigated. Tetragenococcus halophilus CH2-4 and CH6-2 exhibited highest aminopeptidase activities 2.2 U/mL toward Glutamic-pNA. Meanwhile T. halophilus CH6-1 and V7-2 showed highest aminopeptidase activities 1.4 U/mL toward Leucine-pNA.  The total 19 volatile compounds, including esters, alcohols, ketones, phenols, hydrocarbons and sulfur containing compounds were detected in fish broth inoculated with T. halophilus.T. halophilus CH6-2 produced most volatile compounds, 10/19 detected ones in this study.  

Solvent-Induced Chirality in the Hydroboration of Ketones

2008 ◽  
Vol 61 (6) ◽  
pp. 414 ◽  
Author(s):  
Christoph Baldauf ◽  
Nina Dickerhof ◽  
Stefan H. Hüttenhain ◽  
Stefanie Kern ◽  
Nancy Krummrich ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Methyl Ester ◽  
Lewis Acids ◽  
Enantiomeric Excess ◽  
Acid Methyl Ester ◽  
Asymmetric Induction ◽  
Aromatic Ketones ◽  
Positive Effects ◽  
Substrate Structure ◽  
Acid Methyl

The influence of the systematic variation of chiral solvents and of diverse Lewis acids on the asymmetric induction of the hydroboration of acetophenone has been studied. None of the solvents used could surpass lactic acid methyl ester, and for the Lewis acids, ZnCl2 and ZnI2 showed positive effects on the enantiomeric excess (ee) and the conversion. Also, the effect of the substrate structure was investigated by comparing the conversion and ee of eight different ketones. Apparently, the achievable asymmetric induction was higher with aromatic ketones.

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