Carbon 13 nuclear magnetic resonance compounds

Chemical examination of Sarcophyton glaucum collected at Ishigaki island, Okinawa Prefecture, resulted in the isolation of seven cembranoid diterpenes, namely sarcophytol A (3), sarcophytol A acetate (4), sarcophytol B (5), sarcophy-tonin A (6), and minor constituents sarcophytol C (7), D (8), and E (9). These compounds were found to be susceptible to autooxidation while being purified. The structural determination of these compounds was made mainly based on proton and carbon nuclear magnetic resonance (NMR) spectral evidence and degradative studies by ozonolysis. X-ray crystallographic analysis for the two crystalline compounds, sarcophytol B (5) and D (8), has been reported. The total lipid extracts of S. glaucum comprise about 40% sarcophytol A (3), 5% each of sarcophytol A acetate (4) and sarcophytonin A (6), about 1% sarcophytol B (5), and minor amounts of sarcophytol C (7), D (8), and E (9). 

When its term expires, a patent confers on the public the benefits of a chemical invention. It must therefore enable an interested party successfully to repeat the experiments it describes. To ascertain whether these efforts succeed, a helpful patent provides means to recognize compounds of the invention by their chjiracteristic physical properties like melting points and mass-to-charge ratios of molecular ions. Other physical data may replace or supplement the foregoing ones, so many strongly supported patents include details of infrEired, ultraviolet, proton, and carbon nuclear magnetic resonance spectra. 

Fig. 7.21 The displayed hydrogen and carbon nuclear magnetic resonance (NMR) of compound 2 after computation...

Nuclear Magnetic Resonance Spectra of Organometallic Compounds, 3, 1 Of Time and Carbon-Metal Bonds, 9, 1... 

Laughlin et al. [122] analysed chloroform extracts of tributyltin dissolved in seawater using nuclear magnetic resonance spectroscopy. It was shown that an equilibrium mixture occurs which contains tributyltin chloride, tributyl tin hydroxide, the aquo complex, and a tributyltin carbonate species. Fluorometry has been used to determine triphenyltin compounds in seawater [123]. Triph-enyltin compounds in water at concentrations of 0.004-2 pmg/1 are readily extracted into toluene and can be determined by spectrofluorometric measurements of the triphenyltin-3-hydroxyflavone complex. 

Example Isotopic enrichment is a standard means to enhance the response of an analyte in nuclear magnetic resonance (NMR). Such measures gain importance if extremely low solubility is combined with a large number of carbons, as is often the case with [60]fullerene compounds. [19] The molecular ion signals, IVT, of Qo with natural isotopic abundance and of C-enriched Cgo are shown below (Fig. 3.11 for EI-MS of [60]fullerenes cf. Refs. [20-22]). From these mass spectra, the enrichment can be determined by use of Eq. 3.1. For Qo of natural isotopic abundance we obtain Mrceo = 60 x 12.0108 u = 720.65 u. Applying Eq. 

Neutralization with sodium carbonate in an nuclear magnetic resonance (NMR) tube allowed detection of the highly labile parent compound 15 (R = = H). 

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