Using NMR to identify and characterize natural products
The article is impressive in the way it begins with a brief history of structure of natural products, and how its elucidation was a prolonged and challenging process that needed the performing of various degradation and synthetic reactions. Among the most important factors in shaping the degree of use of various spectroscopic techniques was of use of instrumentation( Fischedick 2015). authors of the article therefore leave nothing to chance in their explanation of the history of commercial visible and IR spectrometers. They impressively give an account of how manufacturers at the time permitted natural product chemists to habitually make use of the methods for functional group characterization.
Overall, the article is conclusive and insightful on numerous aspects that relate to how NMR can be used in characterizing and identifying natural products. What remains evident from the article is that the authors touched on all aspects of the topic, and even though some of them were not as detailed as would have been desired, they are nonetheless significant in contributing to the topic (Huff, 2013). The C spectral editing is one area from the article that stands out in C spectral editing .DEPT spectrum lack quaternary carbon and this is a limitation.
The authors, however, can be faulted for dwelling too much on the breakthroughs that were made decades ago as they fail to quickly shift their attention to the advances and discoveries that have been made recently after technological advancements were embraced in the field. Although it is important that the authors give a brief background of how NMR can be used to characterize and identify natural products. (Fischedick 2015). Further, a keen analysis of this article reveals that the articles have failed to cite their guiding research papers, and this greatly jeopardizes their credibility (Roussis, 2014). Some of the sub-topics such as the analysis of complex mixtures by NMR have also been generalized by the article, and such a critical area of investigation should be followed by specific investigations that are medically oriented. The authors, as can be attested to by their own admission, have made various assumptions that might not necessarily be accurate.
The authors noted that operation required a skilled operator who is patience and has good knowledge of physical chemistry. This inhibited the use of NMR .e.g. the Varian HR series of NHMR .Analysis of this article reveals use of X-ray diffraction and mass spectrometry for natural product characterization in the 1950s the determination of a molecular structure from diffraction data .it is worth noting that utility of NMR spectroscopy was still limited by the low sensitivity of continuous wave NMR spectrometers as a result it hindered obtaining C spectra( Fischedick 2015).What remains evident from the article is that the authors confirms that the process is slow and difficult, with estimated intensities of diffraction peaks from camera , has many complicated calculations. Notably in Quantitative H NMRs there is a lot of errors caused by variations in laboratory temperature
What remains evident from the article is that the authors touched on the use of vicinal 1 H-1 H coupling constants and germinal and vicinal 13C-1 H coupling constants caution is needed(Huff, 2013). The use of chemical calculations to supplement experimental data is difficult to determine between alternative possible structures with different stereo chemistries. Meanwhile ,deep analysis of this article reveals that in Probe improvements Most NMR cost far more than regular probes require high routine maintenance and time-consuming to repair .