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Radboud University Nijmegen

History of the LHASA System

LHASA is an interactive computer program designed to assist synthetic chemists in planning syntheses of complex organic molecules. The name is an acronym for `Logic and Heuristics Applied to Synthetic Analysis', which succinctly describes the aims and means of the program. LHASA was started in 1969 as a research project to implement, in a computer program, E.J. Corey's approach to retrosynthetic analysis, and in particular his rules for the recognition of strategic bonds. The predecessor to LHASA was OCSS (Organic Chemical Simulation of Synthesis), developed by Corey and W.T. Wipke in the late 1960s. OCSS was also the predecessor to SECS (Simulation and Evaluation of Chemical Synthesis), developed by Wipke. The CASP (Computer Aided Synthesis Planning) system, used and developed by a consortium of Swiss and West German pharmaceutical companies, is an offshoot of the SECS program.

Extensions to the LHASA system followed rapidly, allowing it to use more extensively and more efficiently the retrosynthetic strategies formulated earlier. At Harvard University, LHASA-1 (for a PDP-1 computer), LHASA-10 (for a PDP-10 computer), and finally in 1981 LHASA-11 (for the DEC VAX series of computers), commonly called LHASA, were developed. Until 1992, LHASA ran exclusively on VAX computers under the VMS operating system. Recently, a serious effort has been made to port the program to the Unix operating system in its various implementations: LHASA now also runs on DECstation (under Ultrix), DEC Alpha (under OpenVMS), Silicon Graphics (under Irix), HP (under HP/UX) machines, and IBM (under AIX) machines.

The LHASA program, now in its fourth decade of continuous development, is maintained by the LHASA Group at Harvard University. Collaborating groups in the UK (ICAMS, Leeds University) and the Netherlands (CMBI, University of Nijmegen) have contributed and are still contributing significantly to the program and knowledge base. In the UK, an industrial consortium called LHASA Ltd has been set up to coordinate the use of the LHASA program and development of the knowledge base, especially with respect to heterocyclic chemistry.

Nowadays, the LHASA system for retrosynthetic analysis is accompanied by other modules which are in effect offshoots of LHASA development:

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Page author: Martin Ott Last update: Wednesday, 1 September 2004