Science And Technology

Elsevier MDL Introduces Enhanced Stereochemical Recognition Capabilities

Elsevier MDL Introduces Enhanced Stereochemical Recognition Capabilities

SAN RAMON, CA - December 18, 2006 - Elsevier MDL is pleased to announce the development of a new algorithm for the determination of stereochemical configuration. The new method, NEMA (Newly Enhanced Morgan Algorithm), delivers a major improvement in stereochemistry perception by extending the recognition to atropisomers, for example biaryls and allenes. NEMA also improves on existing capabilities for handling tetrahedral stereogenic centers and provides more reliable recognition of stereoisomers.

Stereochemistry, which refers to the relative spatial arrangement of the atoms within molecules, is an extremely important tool for studying reactions in the fields of organic, inorganic, biological, physical and supra-molecular chemistry.

"Enhanced stereochemical perception facilitates the chemist’s ability to represent, store and retrieve products produced by the synthesis of increasingly complex molecules with multiple stereogenic centers," said Dr. Trevor Heritage, Senior Vice President and Chief Scientific Officer of Elsevier MDL. "The accurate representation of absolute and relative stereochemical groups is essential to pharmaceutical discovery, and Elsevier MDL is continuing to lead the way as the field of stereochemical representation evolves."

The NEMA algorithm is a major advance over the existing approaches for the determination of stereochemical configuration that have been in use for over 30 years. The new method can be used to calculate equivalence classes for a given molecular structure, to perceive tetrahedral and geometric stereogenic centers, to verify non-tetrahedral stereogenic centers and to correctly identify meso stereoisomers, supporting both 2D and 3D stereochemistry perception.

The NEMA algorithm is used in the soon-to-be-released MDL® Direct 6.0 data cartridge for chemical structure and reaction searching. MDL Direct constitutes the database tier of the integrating MDL® Isentris® system. The NEMA method will be the standard approach to stereochemical recognition used by all MDL products, including the soon-to-be-released MDL® Cheshire 4.0. It is fully backward compatible with existing representations and retains all search and retrieval characteristics of current systems.

A white paper providing a technical description of Elsevier MDL’s NEMA method of stereochemical representation will be available in the near future. For more information, or if you would like to be notified when the white paper is published, contact Keith T. Taylor, Ph.D., M.R.S.C., Senior Product Manager, Elsevier MDL, 925-543-7525,


About Elsevier MDL
Elsevier MDL provides informatics, database and workflow solutions that accelerate successful scientific R&D by improving the speed and quality of scientists' decision making. Researchers around the world depend on Elsevier MDL for innovative and reliable discovery informatics software solutions and services augmented by 400 Elsevier chemistry and life sciences journals and related products. For more information, visit Elsevier is a world-leading publisher of scientific, technical and medical information products and services.

Elsevier is part of Reed Elsevier Group plc, a world-leading publisher and information provider. Reed Elsevier's ticker symbols are REN (Euronext Amsterdam), REL (London Stock Exchange), RUK and ENL (New York Stock Exchange). For more information, visit

About Elsevier
Elsevier is a world-leading provider of information solutions that enhance the performance of science, health, and technology professionals, empowering them to make better decisions, deliver better care, and sometimes make groundbreaking discoveries that advance the boundaries of knowledge and human progress. Elsevier provides web-based, digital solutions — among them ScienceDirect, Scopus, Elsevier Research Intelligence and ClinicalKey— and publishes over 2,500 journals, including The Lancet and Cell, and more than 33,000 book titles, including a number of iconic reference works. Elsevier is part of RELX Group plc, a world-leading provider of information solutions for professional customers across industries.

Media Contact
Keith T. Taylor
Elsevier MDL
Phone: (925) 543-7525