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
Tel./fax +44 (0)1477 533837
wendy@warr.com http://www.warr.com