Useful tools for synthesis planning from the Syngen Program

CINF 85

James B. Hendrickson, Hendrickson@Brandeis.edu, Department of Chemistry (MS 015), Department of Chemistry, Brandeis University, Waltham, MA 02454-9110
The SynGen program for retrosynthetic generation of synthesis routes has not had the usage which it appears to deserve, but its key tools will be useful for anyone in synthesis planning. The program is very fast and will find all the shortest routes to any input target. It has three central features that assure its efficiency: a) digital characterization of structures and reactions; b) organization by basic C,N,O,S skeleton and a starting materials catalog organized by skeleton; and c) rigorously unique canonical numbering of skeletons. The characterization of structures generalizes skeleton and functionality digitally with only four kinds of bonds to skeletal atoms and so hugely abstracts the search space for rapid search. It also generalizes all kinds of reactions by net structural change and so requires no reaction database. The canonical numbering of skeleton allows rapid and reliable comparison of generated structures with the starting material catalog. These are important tools for anyone to use, and our planned revision of SynGen will also provide for preliminary ranking of any large set of possible targets for their ease of synthesis.