Issue #24 resolved
Richard Apodaca
created an issue

Salts containing the "hemisulfate" form are not recognized, for example, "pyridinium hemisulfate" (two pyridines and one sulfuric acid).

The term appears regularly in chemical supplier catalogs.

For charged groups, the behavior of "sulfate" groups is the same as that needed for "hemisulfate". For example, "pyridinium sulfate" gives the same structure that "pyridine hemisulfate" should give.

Comments (2)

  1. Daniel Lowe repo owner

    I've added general support for fractional multipliers. I'm still not absolutely sure my solution is correct in all corner cases, there are some nasty interactions with how OPSIN does charge balancing e.g. in pyridinium hemisulfate, the ratio of 2:1 is determined by the multiplier rather than charge balancing. However in my other test case of potassium carbonate sesquihydrate, charge balancing must be done before taking into account the fractional multiplier. Otherwise the charge balancing will not be applied as it thinks that the number of potassiums/carbonates has been explicitly set to 2.

    Cases like "(R)-3-[2-(2-hydroxymethylpyrrolidin-1-yl)ethyl]-5-methyl-2H-isoquinolin-1-one hemisulfate sesquihydrate" are supported

    I've updated the webservice (opsin.ch.cam.ac.uk) so if you happen to see any bugs let me know.

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