Synthetic Heuristics Applied

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... 

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. 

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... 

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... 

LHASA—Logic and Heuristics Applied to Synthetic Analysis... 

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. 

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). 

Bifunctional systems In the case of bifunctional systems (or molecules) only two alternatives are possible the bifunctional relationships are either "consonant" or "dissonant" (apart from molecules or systems with functional groups of type A to which we have referred to as "assonant"). In the first case, the synthetic problem will have been solved, in principle, in applying the "heuristic principle" HP-2 that is to say, the molecule will be disconnected according to a retro-Claisen, a retro-aldol or a retro-Mannich condensation, or a retro-Michael addition, proceeding if necessary by a prior adjustment of the heteroatom oxidation level (FGI). 

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