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. 2015 May 30:7:23.
doi: 10.1186/s13321-015-0068-4. eCollection 2015.

InChI, the IUPAC International Chemical Identifier

Stephen R Heller  1 , Alan McNaught  2 , Igor Pletnev  3 , Stephen Stein  1 , Dmitrii Tchekhovskoi  1
Affiliations

InChI, the IUPAC International Chemical Identifier

Stephen R Heller et al. J Cheminform. .

Abstract

This paper documents the design, layout and algorithms of the IUPAC International Chemical Identifier, InChI.

Keywords: Chemical identifier; Chemical structure linear notation; IUPAC standard; InChI; InChIKey.

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Figures

Figure 1
Figure 1
Structure, IUPAC name and InChIKey for palytoxin [14].
Figure 2
Figure 2
InChI layered representation of the monoanion of 32P-labelled adenosine triphosphate. Left – input structure; right –core parent structure used by InChI, with canonical atomic numbers.
Figure 3
Figure 3
Both Standard (upper 2 lines under each drawing) and FixedH (lower 2 lines) versions of InChI and InChIKey for mesomers are the same: formamide (left) and nitromethane (right).
Figure 4
Figure 4
Both Standard (upper 2 lines under each drawing) and FixedH (lower 2 lines) versions of InChI and InChIKey for mesomers are the same, as exemplified by Methylene Blue.
Figure 5
Figure 5
Standard versions (upper 2 lines under each drawing) of InChI and InChIKey for tautomers are the same while FixedH versions (lower 2 lines) differ, as exemplified by an isoguanosine derivative.
Figure 6
Figure 6
Stereoisomers of menthol with associated InChI/Keys.
Diagram 1
Diagram 1
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Figure 7
Figure 7
InChIKey layout explained (using caffeine as an example).
Figure 8
Figure 8
Standard (upper line under each drawing) and FixedH (lower line) InChIKeys for the various ionization states of L-lysine.
Figure 9
Figure 9
General workflow of InChI/Key generation.
Diagram 2
Diagram 2
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Diagram 3
Diagram 3
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Diagram 4
Diagram 4
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Diagram 5
Diagram 5
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Diagram 26
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Figure 10
Figure 10
Canonicalization order flowchart.
Figure 11
Figure 11
Establishiment of the canonical atomic numbers for 2-chlorobutane (steps a-e are explained in the text).
See this image and copyright information in PMC

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References

    1. IUPAC - International Union of Pure and Applied Chemistry: Home. [http://www.iupac.org/]
    1. National Institute of Standards and Technology. [http://www.nist.gov/]
    1. InChI Trust: Home. [http://www.inchi-trust.org/]
    1. Heller S, McNaught A, Stein S, Tchekhovskoi D, Pletnev I. InChI - the worldwide chemical structure identifier standard. J Cheminformatics. 2013;5:7. doi: 10.1186/1758-2946-5-7. - DOI - PMC - PubMed
    1. Stein S, Heller S, Tchekhovskoi D, Pletnev I. IUPAC International Chemical Identifier (InChI) InChI version 1, software version 1.04 (2011) Technical Manual. [http://www.inchi-trust.org/download/104/InChI_TechMan.pdf] - PMC - PubMed