Synthetic accessibility assessment

The assessment of synthetic accessibility (SA) of a lead candidate is a task which plays a role in lead discovery regardless of the method the lead candidate has been identified with. In the case of a de novo designed molecule the experimental validation of its activity requires synthesis of the compound. In the case of experimental or virtual screening exploration of the SAR around the hit, synthetic access to the chemotype is required as well. The more difficult the synthesis of the lead candidate is, the more time and resources are needed for the exploration of this particular area of chemical space. Lead candidates are normally prioritized according to criteria such as drug-likeness [1,2], natural-product likeness [3], predicted activity or freedom to operate with respect to intellectual property. Since sooner or later in the drug discovery process the candidates will be ranked, or even eliminated by their synthetic accessibility, it is desirable to include this aspect into... 

Therefore currently the only way to assess the performance of the calculated synthetic accessibility score is to rely on a ranking done by experienced medicinal chemists. 

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