Frequently Asked Questions

When a retrosynthesis search returns no results, there are several approaches to try. First, increase the risk level in your search parameters - by default ChemAIRS® searches at a low risk level, focusing on well-established chemistry. Switching to a higher risk level allows the algorithm to explore more creative and novel routes. You can also manually break the molecule into smaller fragments using the Manual Search function, or run the search in the Process Chemistry module, which allocates more computational resources and is better suited for complex or challenging targets. If you are still not finding results, contact the Chemical.AI team - they can review your specific molecule and help troubleshoot, or identify whether a gap in the database needs to be addressed.

ChemAIRS® ranks routes using a difficulty score - a weighted combination of the number of linear steps and how closely each proposed reaction resembles known, precedented chemistry. The closer a route is to well-established chemistry, the lower the difficulty score. Routes can also be ranked with consideration of your internal ELN data when local deployment is in place, with scores adjusted to reflect real project conditions. ChemAIRS® delivers 10 to 50 prioritized routes per search, and in an internal case study, its top 3 routes aligned with the decisions of expert chemists in 80% of 16 synthetic projects.

Yes. Impurity prediction is the process of identifying potential byproducts that may form during a chemical reaction before it is carried out in the lab. In drug development, discovering impurities late - especially during scale-up - can be extremely costly. ChemAIRS®'s Impurity Prediction module allows you to model a single-step reaction before running it. You input the reactants, conditions, and any known contaminants in the raw materials, including trace impurities from a previous step. Each predicted impurity is accompanied by a confidence score from 0 to 100, and ChemAIRS® shows the proposed reaction mechanism mapped to a real reference reaction for every prediction. You can also upload a proton NMR spectrum and overlay it with predicted NMR spectra to confirm whether a structure matches before running more expensive analyses.

The SA Score, or Synthesizability Assessment Score, is a metric used to evaluate how practical a molecule is to synthesize. It helps chemists and computational teams prioritize which compounds from a virtual library are realistic to make in the lab, before investing time and resources. In ChemAIRS®, the SA Score is calculated based on retrosynthesis rules rather than chemical similarity - which makes it distinct from other tools that can overestimate or underestimate difficulty. The score runs from 0 to 5. A score of 0 means the compound is commercially available. The score increases as the synthesis becomes longer and more complex. ChemAIRS® validated its SA Score against the assessments of a team of medicinal chemists at Merck across over 13,000 molecules, with close alignment. It is designed for high-throughput screening of large virtual and real compound libraries.

No. An SA Score of 5 does not mean the molecule cannot be synthesized. It means the algorithm did not find a straightforward route within the time available for the SA Score calculation. Any compound with a score of 5 can be pushed directly into the Retrosynthesis module for a deeper analysis - routes are often found. SA Score is a prioritization tool, not a yes-or-no gate. It helps teams move from a long list of candidate targets to a short list of realistic first priorities.

Yes. Internal Data Integration is one of the 8 core modules in ChemAIRS®. The platform integrates your in-house reaction data to personalize and improve route recommendations. With local deployment, your internal ELN data, building block libraries, and custom vendor catalogs can all be connected - typically within days. The algorithm reads ELN data without requiring human curation, and learnings are retained locally over time through adaptive learning, meaning the platform continues to improve the more your team uses it.

Yes. From any route in ChemAIRS®, you can export it as a PDF or Word file with a full step-by-step breakdown. You can also generate a Compound List - a CSV file of every building block, reagent, and solvent required for the synthesis - to cross-reference with your inventory or pass to procurement. Routes can be shared with colleagues or supervisors with one click, as long as they have a ChemAIRS® login. You can also bookmark routes and leave comments directly within the platform.

Yes. ChemAIRS® handles stereochemistry in retrosynthesis. For simple chiral molecules with one or a few unrelated chiral centers, ChemAIRS® guides users on how the chirality can be constructed and provides relevant literature references. For molecules with multiple nearby chiral centers, ChemAIRS® focuses on relative configuration and provides supporting references. The platform has also recently added chiral separation and chiral auxiliaries functions, both of which address absolute chiral configurations. A dedicated chirality module is currently in development for more advanced use cases in process chemistry.