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ACD/Labs Blog

Arvin Moser
Hybrid experiments, like an HSQC-TOCSY experiment, add an extra dimension to its interpretation. It is through practice that one can become familiar with interpreting the data easily. For an unknown compound, a 1H -13C HSQC-TOCSY spectrum was collected. There are 8 visible HSQC correlations circled in red and 10 TOCSY correlations circled in blue (numbered...

Arvin Moser
Depending on the mixing time, HSQC-TOCSY experiments generally offer information on both short-range and long-range coupled nuclei. The issue arises in sorting out the HSQC correlations from the TOCSY ones. For an unknown compound, a 1H -13C HSQC-TOCSY spectrum was collected. The expanded region of the spectrum below shows several correlations. How many HSQC-related correlations...

Mikhail Elyashberg
Plaza et al [1] isolated two new unusual depsipeptides, aetheramides A and B. Here we will discuss the computer-assisted structure elucidation (CASE) of aetheramide B (molecular formula C41H54N2O9) using ACD/Structure Elucidator.

Arvin Moser
With any experimental data, producing a list of scenarios that are consistent with the data can help guide an elucidator through the problem while ensuring nothing gets overlooked. For an unknown compound, the 1H -13C HMQC spectrum shows a CH group with a correlation at 7.0 and 113.0 ppm. Is the carbon hybridization an sp2 or...

Arvin Moser
Coupling information is very useful in locating the position of an atom in relation to other atoms. This puzzle covers one such example. For an unknown compound1, the 13C assignment is not clear for carbons 116 or 134 ppm. The 13C NMR spectrum shows the 19F-13C coupling for the carbon at 116 ppm as 23.7...

Arvin Moser
Coupling information is very useful in locating the position of an atom in relation to other atoms. This puzzle covers one such example. For an unknown compound1, a di-substituted phenyl ring with a fluorine substituent was deciphered. The 13C NMR spectrum below shows two 13C signals split due to 19F-13C coupling. Which carbon, chemical shift...

Mikhail Elyashberg
El Aouad at al isolated a new naphthopyrone (structure 1) named Lasionectrin (molecular formula C19H20O6) with antiplasmodial properties from fermentation broths of a Lasionectria species. The article constitutes the first account on the isolation of a natural product from fungi of this genus.

Arvin Moser
Post data processing can both be a good thing or a bad thing. With any experimental data, too much processing can affect some critical pieces of information. A 1H NMR spectrum was collected for an unknown compound. An exponential function was applied to the data to help improve the signal-to-noise. A line broadening of 0.0...