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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...

Searching for unknowns across an internal library or database can serve as a major time saver. A more accessible database is the Internet. Many chemists and elucidators search the World Wide Web using a mass, a molecular formula or a fragment. Be aware that proprietary data sent over the Internet runs the risk of being...

A previous blog described the Internet as a valuable tool in searching for previous work based on a molecular formula. In addition to searching the Internet “directly”, certain online sites can assist and facilitate the search process. Some of these sites are free while others have a fee. Be aware that the Internet is full...

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...

With the help of ACD/Labs’ software, PharmaSea researchers have dereplicated more than 300 extracts, and, as a result, have identified 10 novel compounds that merit further research. Prof. Marcel Jaspars, head of the Marine Biodiscovery Centre at the University of Aberdeen, and project leader of PharmaSea, discusses the PharmaSea project in detail here.

We will be hosting several sessions on What’s New in version 2023 of ACD/Labs software over the coming weeks. Subject areas will include NMR, mass spectrometry, chromatography, Percepta, and more. If you are interested in being notified about future sessions, please contact us. What’s New in MS This session will highlight What’s New in Version...

To identify co-eluting components on a chromatogram, one searches for any distinct differences between the components. There are basically three criteria to check the XICs (extracted ion chromatograms) for to confirm whether the m/z signals pertain to the same component: line shape, signal apex and retention time range. The XICs for m/z 188.1 and 205.1...

In searching for novel antibiotics, Thongbai et al have focused on tropical basidiomycetes from Asia. The research led to the isolation of unprecedented antimicrobial metabolite Gymnopalynes A (molecular formula C12H7O2Cl). Though the molecule is small and relatively simple, elucidation of its structure is not straightforward. With this in mind we used this problem to illustrate some nuances associated with utilization of ACD/Structure Elucidation.

In search for bioactive compounds from the mushroom Stropharia rugosoannulata, Wu et al discovered four novel steroids named strophasterols A, B, C, and D which contained a very unique and unprecedented carbon skeleton. Here we will describe the computerized structure determination of Strophasterol A (molecular formula C28H44O4).