LHASA , Logic and Heuristics Applied to Synthetic

LHASA—Logic and Heuristics Applied to Synthetic Analysis 

Central Research and Develop. Dept., E. I. du Pont de Nemours and Co., Wilmington, Del. 19898 

of Chemistry, Harvard University, Cambridge, Mass. 02138 

Despite the wealth of knowledge about various chemical reactions, there exists no formal framework of interrelationships to guide the chemist in the synthesis of even moderately complex molecules. The LHASA (Logic and Heuristics Applied to Synthetic Analysis) project is an attempt to codify and organize the techniques used in organic synthesis. 

One important aspect of the project has been the writing of a general purpose computer program which will aid the laboratory chemist and will employ both the basic and more complex techniques for synthetic design as elucidated by this study. The program (hereafter also called LHASA) is intended to propose a variety of synthetic routes to whatever molecule it is given. The responsibility for final evaluation of the merit of the routes lies with the chemist. The program is to be an adjunct to the laboratory chemist as much as any analytical tool. 

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The computer-assisted synthetic analysis designated OCSS (organic chemical simulation of synthesis) and LHASA (logic and heuristics applied to synthetic analysis) were designed to assist chemists in synthetic analysis by Corey et LHASA generates trees of synthetic intermediates from a target molecule by analysis in the retrosynthetic direction. 

Series 61, American Chemical Society, Washington, DC, 1977, pp. 1-32. LHASA—Logic and Heuristics Applied to Synthetic Analysis. 

Research into the use of digital computers to assist in the derivation of synthetic routes to complex molecules has been in progress for several years at Havard. The program is called LHASA Logic and Heuristics Applied to Synthetic Analysis). The research is being carried out by a team headed by Corey. l... 

The evolution of molecular graphics (7) is described in an earlier ACS Symposium Series book (77) which acts as an interesting precursor to this present volume. Chemical reaction systems such as LHASA (Logic and Heuristics Applied to Synthetic Analysis) 18) and SECS (Simulation and Evaluation of Chemical Synthesis) (79) had long used graphics but it was some time before the first in-house, proprietary system appeared, attracting much interest in the chemical and pharmaceutical industries. This was Upjohn s Compound Information System, COUSIN 20-21). 

In 1969 Corey and Wipke [7] reported the program OCSS (Organic Chemical Simulation of Synthesis) which was the precursor of one of the most powerful programs known at present which has been named LHASA (the acronym of Logic and Heuristics Applied to Synthetic Analysis) [5b] [8]. Since then, different... 

Logic and Heuristics Applied to Synthetic Analysis (LHASA) is an expert system for synthesis planning that assists chemists in designing efficient routes to target molecules for organic synthesis. 

Logic and Heuristics Applied to Synthetic Analysis for retrosynthetic analysis of organic compounds using reactions stored as transforms in knowledge base. APSO, a teaching version of LHASA that displays successful and unsuccessful... 

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