Skip To Content

Search for: AT-queryhelp.html

The nomenclature rules for organic compounds set by the International Union of Pure and Applied Chemistry (IUPAC) committee (http://www.iupac.org/) do offer flexibility in some areas especially in cases where old publications have old terms. Below are some examples. The answers for the structures, as based on the IUPAC nomenclature rules, are listed below. Some links...

Originally published in 2008, the underlying essence of a structure elucidation process is to structurally distinguish an unknown from a set of possible isomers. This is evident by the number of possible isomers for a given molecular formula. The chart below divides isomers into three groups: Structural/Constitutional/Regio, Spin and Stereo/Spatial isomers. Wikipedia links are included...

Wolfgang Robien and Modgraph Consultants, Ltd. have responded to my latest comments and findings on the evaluation of our NMR predictions vs. the NMRShiftDB.  Let me first begin by saying that over the last 24 hours, ACD/Labs was informed by Modgraph representation that my claims on this blog regarding CSEARCH and Modgraph’s NMRPredict were not...

NMRShiftDB is an open source collection of  chemical structures and their associated NMR shift assignments. The database is generated as a result of contributions by the public and currently contains 19,958 structures with 214,136 assigned carbon chemical shifts. Turns out, it is also a GREAT resource for evaluating the accuracy of NMR predictions. Several weeks...

Perfect, of course. But I think we can all realize that it’s not realistic for NMR predictions to be perfect. Chemistry and nature just has too much structural diversity to throw at us. Furthermore, even when the exact structure is in the prediction database, the result may not be perfect. Effects such as solvent, temperature,...

If you have read my earlier post, you will be aware of Wolfgang Robien’s critique of the NMRShiftDB. Following this critique, Tony Williams from the ChemSpider Blog  and Peter Murray-Rust from the Unilever Cambridge Centre for Molecular Informatics replied to Wolfgang’s comments. Well now, it appears that Wolfgang has responded to Tony’s comments.You can find...

Peter Murray-Rust and Tony Williams have added their two cents to this debate on their respective blogs. Peter provides a great justification on providing open access to scientific information: In the case of NMRShiftDB I am firmly of the opinion that it leads the way in opening access to scientific information. If the community wishes...

So the NMRShiftDB and our comparison to Modgraph and CSEARCH has caused quite a stir. Currently we are still awaiting Modgraph’s response on the following two points: What is the overlap between NMRShiftDB and Modgraph’s NMR prediction databases? Further, with several different database sources how much duplication of data exists across the Modgraph databases? Once that...

In yesterday’s post I pointed you to an article that has become the most accessed article of all time in the Journal of Cheminformatics, co-authored by representatives of ACD/Labs. This article is a very comprehensive outline of the different approaches, developments, and successes of the development of CASE (Computer-Assisted Structure Elucidation) systems . I hope...

I was flying home from Europe yesterday and was watching the Oscar award-winning movie “Good Will Hunting” starring Matt Damon, Robin Williams, Ben Affleck, and Minnie Driver: One thing I missed the first time I saw the movie, was a moment where Matt Damon’s character shows up at Minnie Driver’s dorm room to ask her...