February 26, 2009
by Arvin Moser, Team Manager, Application Scientists, ACD/Labs
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 intercepted.
Searching the Internet via Google™ for the molecular formula C17H11N5 produced 787 hits with Letrozole appearing in the first dozen hits or so. Using a variation of the molecular formula C17 H11 N5 with the elements spaced out produced over 34,000 hits without any clear reference to Letrozole.
787 hits equates to 787 Google hits so no idea how many structures? Search ChemSpider for C17H11N5 using a formula search gives you 43 hits in 0.46 seconds and each is a unique structure. Letrozole is number 5 in the list: http://www.chemspider.com/Chemical-Structure.3765.html and links to the Wikipedia article etc. using Google for those types of searches gives too much data
Hello Tony,
The 787 hits are the total hits listed by Google and do not necessarily represent a link to a complete structure.
My next blog is going to be geared towards other Internet venues that offer search capabilities without being too specific.
Arvin, if you went to the structure for Letrozole here: http://www.chemspider.com/Chemical-Structure.3765.html and clicked on the Embed link (as described here: http://www.chemspider.com/blog/why-are-chemical-structures-like-youtube-videos.html) and used the structure from ChemSpider then your blog post would be linked directly to ChemSpider.
Good to see that you inserted the structure from ChemSpider. Please post my earlier comment so that people know about this technology. It’s very enabling
Arvin, nice post. The number of public-facing structure-searchable databases has been growing for some time:
http://depth-first.com/articles/2007/01/24/thirty-two-free-chemistry-databases
It’s a great time for chemical informatics – a much-needed refocusing. The challenge will be getting these systems to talk to each other.
You might also try Google + InChI key. The interesting thing about InChI Key is that if your compound is unknown, it’s very difficult, if not impossible, for a third party to learn what structure you were searching for:
http://depth-first.com/articles/2008/12/02/five-questions-about-the-inchi-resolver
THere are a few issues with inChiKey and that is the variation that can occur. See the presentation here: http://tinyurl.com/bpgg2m
That said…a search on the InChIkey for Letrazole does give a few hits across various databases.