1H NMR Analysis and Bioautography Screening of Methanol Extract of Sargassum wightii by Chromatographic Separation

The methanol extract of whole plants of Hygrophila schulli Buch.-Ham. was subjected to repeated chromatographic separation and purification processes to isolate its chemical constituents. A total of three compounds were isolated which have been characterized as stigmasterol, lupeol and lup-20(29)-ene-3β,23- diol on the basis of 1H NMR spectral evidence and confirmed by comparing with published data, as well as co-TLC in case of stigmasterol and lupeol. This is the first report of lup-20(29)-ene-3β,23-diol from this plant.

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Polyhydroxyalkanoate quantification in organic wastes and pure cultures using a single-step extraction and 1H NMR analysis

Water Science & Technology ◽

10.2166/wst.2012.273 ◽

2012 ◽

Vol 66 (5) ◽

pp. 1000-1006 ◽

Cited By ~ 12

Author(s):

Elisabeth Linton ◽

Asif Rahman ◽

Sridhar Viamajala ◽

Ronald C. Sims ◽

Charles D. Miller

Keyword(s):

1H Nmr ◽

Azotobacter Vinelandii ◽

Nile Blue ◽

Agricultural Waste ◽

Accurate Method ◽

Single Step ◽

Proton Nuclear Magnetic Resonance ◽

Copolymer Composition ◽

Nmr Analysis ◽

Nmr Method

In this study, a proton nuclear magnetic resonance (1H NMR) method was developed to quantitatively analyze polyhydroxyalkanoate (PHA) content in Cupriavidus necator H16, Azotobacter vinelandii AvOP, and mixed microbial cultures from the effluent of an agricultural waste treatment anaerobic digester. In contrast to previous methods, a single-step PHA extractive method using deuterated chloroform was established, thereby facilitating direct 1H NMR analysis. The accuracy of the method was verified through comparison with well-established gas chromatography (GC) methanolysis techniques. Nile blue fluorescence staining was also carried out to serve as an independent and qualitative indicator of intracellular PHA content. The results indicate that the 1H NMR method is appropriate for rapid and non-destructive quantification of overall PHA content and determination of PHA copolymer composition in a variety of cultures. Notably, this technique was effective in measuring PHA content in full-strength waste samples where high concentrations of background impurities and organic compounds are present. The straightforward procedures minimize error-introducing steps, require less time and materials, and result in an accurate method suitable for routine analyses.

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Iridium-Catalyzed Triborylation of 3-Substituted Indoles

Australian Journal of Chemistry ◽

10.1071/ch15393 ◽

2015 ◽

Vol 68 (12) ◽

pp. 1810 ◽

Cited By ~ 7

Author(s):

Andrew S. Eastabrook ◽

Jonathan Sperry

Keyword(s):

1H Nmr ◽

Nmr Analysis ◽

One Pot ◽

Substitution Pattern ◽

The Third

Readily available 3-substituted indoles undergo a one-pot iridium-catalyzed triborylation at the C2, C5, and C7 sites. 1H NMR analysis indicates borylation at C2 and C7 occurs first (no monoborylated product is observed), with the third borylation occurring as a separate, distinct step that is sterically directed to C5 by a combination of the substituent at C3 and the boronate at C7. The resulting tetrasubstituted indoles possess a substitution pattern that is cumbersome to prepare using existing methods.

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Rarely Occurring Natural Products Isolated from Vincetoxicum stocksii

Journal of the chemical society of pakistan ◽

10.52568/000781/jcsp/41.04.2019 ◽

2019 ◽

Vol 41 (4) ◽

pp. 695-695

Author(s):

Saima Khan Saima Khan ◽

Muhammad Imran Tousif Muhammad Imran Tousif ◽

Naheed Raiz Naheed Raiz ◽

Mamona Nazir Mamona Nazir ◽

Mahreen Mukhtar Mahreen Mukhtar ◽

...

Keyword(s):

Natural Products ◽

Methanol Extract ◽

High Resolution Mass Spectrometry ◽

Ethyl Acetate Fraction ◽

2D Nmr ◽

Ethyl Carbamate ◽

Carbamic Acid ◽

Nmr Analysis ◽

Nmr Techniques ◽

Resolution Mass

Silica gel column chromatography of the ethyl acetate fraction of methanol extract of Vincetoxicum stocksii resulted in the separation of three new rarely occurring natural products; [4-(4-(methoxycarbonyl)benzyl)phenyl] carbamic acid (1), bis[di-p-phenylmethane]ethyl carbamate (2), methyl 2-hydroxy-3-(2-hydroxy-5-(3-methylbut-2-enyl)phenyl)-2-(4-hydroxyphenyl) propanoate, stocksiloate(3), along with five known compounds; 1-(4-hydroxy-3-methoxyphenyl)-1,2,3,-propanetriol (4), feruloyl-6-O-β-D-glucopyranoside (5), 4-hydroxy-3,5-dimethoxybenzoic acid (6), apocynin (7) and vincetomine (8). The structures of compounds 1 and 2 were established with help of 1D, 2D-NMR techniques and high resolution mass spectrometry, whereas, compound 3 could only be characterized tentatively by 1D, 2D-NMR techniques. Compounds 1 is new compound while 2 is synthetically known but never been reported from natural source. The known compounds were identified due to 1D NMR analysis and in comparison with the literature values. Compounds 1-3 were found inactive in an anti-urease assay.

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