Efficient Methylation of Carboxylic Acids With Potassium Hydroxide/Methyl Sulfoxide and Iodomethane

Ávila-Zárraga, José Gustavo; Martı́nez, Roberto

doi:10.1081/scc-100104469

Cited by 29 publications

(21 citation statements)

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“…Extension to another class of metabolites using this approach opens up additional possibilities for the analysis of complex samples and potentially for improved disease detection. For example, we have also had success in derivatizing carboxylic acid groups of metabolites in urine by using excess methyl iodide (37), which further expands the types of metabolite profiles accessible with the method. Combinations of derivatization, sensitivity-enhanced NMR experiments such as 2D HSQC, and pattern recognition methods such as principle component analysis could be potentially useful in biomarker discovery for a number of diseases.…”

Section: Resultsmentioning

confidence: 99%

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR

Shanaiah

DeSilva

Gowda

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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We report a chemical derivatization method that selects a class of metabolites from a complex mixture and enhances their detection by 13 C NMR. Acetylation of amines directly in aqueous medium with 1,1 -13 C2 acetic anhydride is a simple method that creates a high sensitivity and quantitative label in complex biofluids with minimal sample pretreatment. Detection using either 1D or 2D 13 C NMR experiments produces highly resolved spectra with improved sensitivity. Experiments to identify and compare amino acids and related metabolites in normal human urine and serum samples as well as in urine from patients with the inborn errors of metabolism tyrosinemia type II, argininosuccinic aciduria, homocystinuria, and phenylketonuria demonstrate the method. The use of metabolite derivatization and 13 C NMR spectroscopy produces data suitable for metabolite profiling analysis of biofluids on a time scale that allows routine use. Extension of this approach to enhance the NMR detection of other classes of metabolites has also been accomplished. The improved detection of low-concentration metabolites shown here creates opportunities to improve the understanding of the biological processes and develop improved disease detection methodologies.carbon-13 ͉ inborn errors of metabolism ͉ metabolite profiling ͉ metabolomics ͉ metabonomics T he metabolic profile in biofluids represents a snapshot of ongoing biological processes in the human body. The presence of a particular metabolite, panel of metabolites, or a certain ratio of metabolites can indicate normal homeostasis, a response to biological stress, or even a specific disease state. Conventional medical diagnostic methods are typically based on the selective detection of a single or a few biochemical parameters that are associated with a given disease. A major challenge in the present practice of clinical medicine is the lack of suitable biomarkers and bioanalytical technologies for earlier detection of numerous diseases. Metabolic profiling or metabolomics, defined as the analysis of multiple biofluid metabolites in parallel, holds the promise of earlier disease detection and improved understanding of systems biology (1-3). Early indications of this potential have been reported for the detection of several diseases, including inborn errors of metabolism, cardiovascular diseases, and cancer (4-7).NMR and mass spectrometry are the two most often used analytical methods for metabolite profiling because of their high resolution and rich data content (8)(9)(10)(11)(12)(13)(14). Although mass spectrometry is the more sensitive technique, NMR provides broad coverage of the metabolome by detecting all of the (hydrogencontaining) metabolites present in the biofluid simultaneously, with excellent reproducibility and only limited sample pretreatment. Thus, for example, many classic inborn errors of metabolism (IEM) can be diagnosed by the use of 1 H NMR spectroscopy of body fluids (15-17). Several of the IEM are associated with the accumulation of amino acids as metabolites in serum an...

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Section: Resultsmentioning

confidence: 99%

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR

Shanaiah

DeSilva

Gowda

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…[1]) or soil organic matter (methylation, Eq. [2]):

\begin{matrix} {CH}_{3} I + OM - XH \to {CH}_{3} - X - OM + {normalI}^{-} + {normalH}^{+} \end{matrix}

where ‐XH represents nucleophilic functional groups (e.g.,‐NH 2 ,‐NH,‐SH,‐OH,‐COOH) of soil organic matter (Gan and Yates, 1996; Avila‐Zárraga and Martínez, 2001). The reported half‐life of MeI in mineral soils ranges from 11 to 43 d, (Gan and Yates, 1996; Zheng et al, 2003), greater than that of other soil fumigants including 1,3‐dichloropropene (1,3‐D), chloropicrin, and methyl isothiocyanate (t 1/2 < 10 d).…”

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confidence: 99%

Degradation of Methyl Iodide in Soil: Effects of Environmental Factors

Guo

Gao

2009

J of Env Quality

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Methyl iodide (MeI) is a promising alternative to the phased-out fumigant methyl bromide (MeBr); however, there are concerns about its environmental fate following soil fumigation. Laboratory experiments were conducted to investigate the effect of various environmental factors on the rate of MeI degradation in soil. The chemical was added to soil at 48.6 mg kg(-1) and incubated under different conditions. The MeI degradation rate in soil was determined by extracting and measuring residual concentrations over a 15 d incubation period. In soil, MeI degradation followed availability-adjusted first-order kinetics. At 20 degrees C MeI had a calculated half-life of 32 d in a sandy loam containing 4.3 g kg(-1) of organic carbon. It degraded more rapidly as temperature increased, exhibiting a half-life of 23 d at 30 degrees C. Amendment with 10% cattle manure shortened the half-life to 4 d at 20 degrees C. In both unamended and manure-amended soils, the half-life of MeI greatly increased as the organic matter (OM) was removed and it only slightly increased in soils that were sterilized, indicating predominance of chemical reactions in MeI degradation. Soil texture, mineralogy, and moderate moisture content had little influence on MeI degradation. The degradation slowed as the chemical application rate increased. The results suggest that environmental factors, especially soil temperature and organic amendments, should be considered in combination with the minimum effective MeI application rate for achieving satisfactory pest-control efficacy, reducing atmospheric volatilization, and minimizing groundwater contamination.

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“…The 4 J H-C correlations observed from H-3 and H-5 to the carboxylic carbon at δ C 170.2 (C-10) and from H-3′ and H-5′ to δ C 167.3 (C-10′) conducted the carboxylic groups to be located at C-1 and C-1′, respectively. In order to establish the connection of both aromatic rings A and B, compound 10 was methylated [ 17 ] to form an analogue 10a ( Figure 4 ), which displayed four methoxy resonances in the 1 H NMR spectrum. The HMBC interactions of 10a between δ H 3.92 (3H, s, OMe)/δ C 168.5 (s, C-10), δ H 3.85 (3H, s, OMe)/δ C 157.3 (s, C-2), δ H 3.86 (3H, s, OMe)/δ C 158.6 (s, C-2′), and δ H 3.89 (3H, s, OMe)/δ C 161.9 (s, C-4′), clarified an ester bond formed across C-4 and C-10′.…”

Section: Resultsmentioning

confidence: 99%

New Polyphenols from a Deep Sea Spiromastix sp. Fungus, and Their Antibacterial Activities

et al. 2015

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Eleven new polyphenols namely spiromastols A–K (1–11) were isolated from the fermentation broth of a deep sea-derived fungus Spiromastix sp. MCCC 3A00308. Their structures were determined by extensive NMR data and mass spectroscopic analysis in association with chemical conversion. The structures are classified as diphenyl ethers, diphenyl esters and isocoumarin derivatives, while the n-propyl group in the analogues is rarely found in natural products. Compounds 1–3 exhibited potent inhibitory effects against a panel of bacterial strains, including Xanthomanes vesicatoria, Pseudomonas lachrymans, Agrobacterium tumefaciens, Ralstonia solanacearum, Bacillus thuringensis, Staphylococcus aureus and Bacillus subtilis, with minimal inhibitory concentration (MIC) values ranging from 0.25 to 4 µg/mL. The structure-activity relationships are discussed, while the polychlorinated analogues 1–3 are assumed to be a promising structural model for further development as antibacterial agents.

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Efficient Methylation of Carboxylic Acids With Potassium Hydroxide/Methyl Sulfoxide and Iodomethane

Cited by 29 publications

References 50 publications

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR

Degradation of Methyl Iodide in Soil: Effects of Environmental Factors

New Polyphenols from a Deep Sea Spiromastix sp. Fungus, and Their Antibacterial Activities

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Efficient Methylation of Carboxylic Acids With Potassium Hydroxide/Methyl Sulfoxide and Iodomethane

Cited by 29 publications

References 50 publications

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced 13 C NMR

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced 13 C NMR

Degradation of Methyl Iodide in Soil: Effects of Environmental Factors

New Polyphenols from a Deep Sea Spiromastix sp. Fungus, and Their Antibacterial Activities

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Product

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Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR

Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced ¹³ C NMR