Recent advances in capillary gas chromatographic techniques and in cmr spectroscopy have greatly assisted in the analysis of complex mixtures of volatile natural products and in structural assignment of new natural products. In this monograph, the authors, who are employed at Bruker Analytische Messtechnik and in the Department of Pharmaceutical Biology at the University of Würzburg, respectively, present extensive charts showing the capillary gas chromatograms and cmr spectra of a variety of essential oils and their constituents.
SynopsisThe natural abundance 15N nmr spectra of linear polysarcosine (DP = 35) has been recorded in Me2SO and H20 solution. Because of cisltrans isomerization at the peptide bond, a broad signal with several splittings was observed. These splittings appear to reflect the influence of three peptide bonds on a single N atom. The 15N signals from the sequence polypeptides (P-Ala-Sar,Gly),, and (B-Ala-Sar-D,L-Ala), also show a cisltrans splitting, as well as chemical shifts which are dependent on the peptide sequence. The tertiary nitrogen of the sarcosyl residue has a T I relaxation time which is longer than the 2'1 for secondary nitrogens of the other amino acids. The nuclear Overhauser effect is also discussed.
Apiaceae, Pimpinella anisum, Essential oil, 13 C NMR From the essential oil of Pimpinella anisum fruits a hitherto unknown type of phenylpropane was isolated. The mass, infrared, and 13 C NMR spectra indicate, that the unknown is a 2-methyl-butyric acid ester of 2-hydroxy-5-methoxy-
The structures of the previously reported 1 : 1 adducts of the furan-2.3-dione 8 and aryl isocyanides 2 and their products with nucleophiles are reassigned with the aid of X-ray diffraction,
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