This message from Alan McNaught mcnaught@ntlworld.com may be of interest to subscribers: A new beta-release of the InChI software is now available from the IUPAC web site (see www.iupac.org/inchi). The principal new features of this release are: (1) A fixed-length (25-character) condensed digital representation of the Identifier to be known as InChIKey. In particular, this will * facilitate web searching, previously complicated by unpredictable breaking of InChI character strings by search engines * allow development of a web-based InChI lookup service * permit an InChI representation to be stored in fixed length fields * make chemical structure database indexing easier * allow verification of InChI strings after network transmission. An example of InChI with its InChKey equivalent is shown below. There is a finite, but very small probability of finding two structures with the same InChIKey. For duplication of only the first block of 14 characters this is 1.3% in a thousand million, equivalent to a single collision in one of 75 databases of one thousand million compounds each. ______________________________________________________________ Caffeine: InChI=1/C8H10N4O2/c1-10-4-9-6-5(10)7(13)12(3)8(14)11(6)2/h4H,1-3H3 InChIKey=RYYVLZVUVIJVGH-UHFFFAOYAW First block (14 letters), encodes molecular skeleton (connectivity): RYYVLZVUVIJVGH Second block (8 letters), encodes proton positions (tautomers), stereochemistry, isotopes, reconnected layer: UHFFFAOY Flag character, indicates InChI version, presence/absence of fixed H layer,isotopes, and stereochemistry: A Check character: W _______________________________________________________________ (2) Restructured InChI-generating software that separates key steps in its creation from an input chemical structure file. Among other uses, this allows checking of intermediate results to enable easier testing and development of InChI-based applications. (3) Bug fixes designed to withstand malicious attempts to attack a Web server by providing a specially designed InChI string input to InChI binaries. We would welcome reports of your experiences with this new release and, of course, any problems. Alan McNaught (InChI project coordinator) Steve Heller Igor Pletnev Steve Stein Dmitrii Tchekhovskoi Dr. Wendy A. Warr Wendy Warr & Associates 6 Berwick Court, Holmes Chapel Cheshire, CW4 7HZ, England Tel./fax +44 (0)1477 533837 wendy@warr.com http://www.warr.com