Project Details InChI Requirements for Representation of Markush Structures

Project No.:
Start Date:
01 March 2010
End Date:
30 September 2015


To establish requirements for extending the applicability of the IUPAC International Chemical Identifier to Markush structures.

> Link to InChI subcommittee


The IUPAC International Chemical Identifier (InChI) algorithm is now well established as a powerful means of denoting a well-defined chemical structure as a unique machine-readable character string, suitable for electronic data storage, searching and exchange. The IUPAC Division VIII InChI Subcommittee is now working on widening the range of applicability of the Identifier, and with this in mind is creating a number of projects designed to facilitate various extensions. In each case the aim is to define precisely the requirements for structural representation in areas of chemistry not currently handled satisfactorily by InChI, bearing in mind that these requirements are to be translated into extensions of the InChI algorithm. Discussions will take place by e-mail and at two face-to-face (annual) meetings. Once established, the requirements will be applied to the necessary software development by contractors appointed and paid by the InChI Trust, a non-profit entity funded by external organizations that use and benefit from the InChI algorithm. The present project is devoted to representations of Markush structures.


Jan 2012 update: This InChI project is the most complex undertaken to date. The initial recommendations have been submitted, but financing of the work still needs to be sorted out.

In September 2011, version 1.04 for Standard and Non-Standard InChI/InChIKey was released. Read more in Chem. Int. Jan 2012 issue.