As I am reading a book called "Symmetry in Chemistry" (H. H. Jaffé and M. Orchin) I thought I would try out a couple of examples that they use. One is 1,2-dichlorocylopropane : which is, apparently, dissymmetric because it has a symmetry element (a C2 axis) but is optically active. Incidentally, wedges can look horrible in small structures - this is why: The box around the hydrogen is shaded in grey, to show the effect of overlap. A possible fix might be to shorten the wedge, but sadly this would require working out the bounds of the text when calculating the wedge, which has to be done at render time. Oh well. Another interesting example is this 'spiran', which I can't find on ChEBI or ChemSpider: Image again courtesy of JChempaint . I guess the problem marker (the red line) on the N suggests that it is not a real compound? In any case, some simple code to determine potential chiral centres (using signatures) finds 2 in the cyclopropane structure, and 4 in the ...
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2) From the ebi ftp site - I /think/ the ChEBI team meant it to be public, but I will ask them
3) Probably not, they have a good website for this purpose.
4) Maybe, but again, depending on the team.
It is a nice test for bioclipse, but there are other similar tests, in a way.
* Chebi_lite.sdf file contains only the chemical structure, ChEBI identifier and ChEBI Name.
* Chebi_complete.sdf file contains all the chemical structures and associated information.