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ACD/Labs Blog

Arvin Moser
The previous blog described two general approaches to analyzing data for an unknown compound: broad and focused approaches. The table below lists the general advantages of broad and focused approaches for a structure elucidation. Depending on the data at hand, one approach can be considered the better choice. An elucidation where lots of background information...

Arvin Moser
There are 2 general approaches to handling data for an unknown compound. A. Start from a broad standpoint and work to narrow down the result(s). An example of this approach is to treat uncertain correlations on an HMBC as 4J coupling rather than as 3J coupling. or B. Start at a focused point and work...

Arvin Moser
Just as there are a variety of fishes in the sea, structure elucidators come in a variety of forms. What makes a qualified elucidator good? Yeah, luck and natural talent can play a role sometimes but it is not an exclusive club by any means. A good elucidator is typically ambitious with a wealth of...

Arvin Moser
Failures, as are successes, are an integral part of a structure elucidator’s role. What differentiates a good elucidator from a bad one is the capability of an elucidator to learn from his/her failures. The most common obstacle that can hold a structure elucidation process from becoming a success is structural bias. (This is based on...

Arvin Moser
Attempting a challenging structure elucidation of an unknown and being unable to solve the problem can put a damper on a hectic workload and possibly on your skills as an elucidator. Emotionally, the excitement of working on a challenging elucidation problem leads into frustration — results are what count. Subsequently, the elucidator faces the following...

Joel Michalski
The involvement of several scientists in the development of Computer-Aided Structure Elucidation (CASE) methods has resulted into the development of a series of expert systems based on 2D NMR data utilization. R. Dunkel has also developed a series of software algorithms and applications that claim to elucidate chemical structures on the spectrometer. Dunkel, in collaboration...

Ryan Sasaki
In fact, to borrow a phrase from a colleague, this might be the defacto article on Computer Assisted Structure Elucidation (CASE) for the next decade! This article written by Mikhail Elyashberg, Antony Williams, and Gary Martin spans across two issues of the review journal, Progress in Nuclear Magnetic Resonance Spectroscopy.  This article entitled, entitled, "Computer-Assisted...

Arvin Moser
A biased elucidation is an elucidation where the chemist makes certain assumptions about the data at hand based on a previous experience(s) and not deviating from it. Depending on the elucidation, it can be a good thing or a very bad thing. As a good thing, it can speed up the time spent on an...

Arvin Moser
In light of the posting by Oliver Fiehn’s group (http://fiehnlab.ucdavis.edu/projects/Seven_Golden_Rules/Ring-Double-Bonds/), I’ve decided to blog some compounds I’ve encountered in the lab. Using the 2nd formula from the previous blog (http://acdlabs.typepad.com/elucidation/2008/03/rings-double-bo.html), for some cases the RDBE calculation will work if the correct atom valence is known. Note: the nitrochloroform compound can be drawn more than one...

Joel Michalski
The validation of the performance of a neural network based 13C NMR prediction algorithm using a test set available from an open source publicly available database, NMRShiftDB, is described. Since similar work has been reported online for another algorithm we compared the results with the errors determined using Robien’s CNMR Neural Network Predictor using the...