Free AI Retrosynthesis Tool Online
Enter a target SMILES or draw a structure. Routes come from AI retrosynthesis with optional library evidence and literature links.
AI retrosynthesis tools What is retrosynthesis How to do retrosynthesis Target Catalog Aspirin Sitemap
What this AI retrosynthesis tool does
ChemicalTool Reaction is a free online retrosynthesis tool. Enter a target molecule as a SMILES string, or draw it in the built-in structure editor, and the AI proposes up to five retrosynthetic routes that break the target down into simpler, commercially available starting materials. Each route shows the intermediate structures, the disconnection used at every step and, where available, supporting reaction evidence and literature links.
How to use it
- Enter the target. Paste a SMILES string or click Draw structure to sketch the molecule.
- Set the search. Choose the maximum number of routes (1–5) and a time limit. Longer limits help with complex targets.
- Optional evidence. Turn on Enrich evidence to look for related reactions in the reaction library.
- Review the routes. Compare routes by number of steps and starting materials, open each step for details, and save the job to your history.
Example synthesis routes
- Aspirin synthesis – from phenol via salicylic acid
- Paracetamol (acetaminophen) synthesis – from 4-nitrophenol
- Caffeine synthesis – Traube route via theophylline
- Phenol synthesis – cumene process and Dow process
- Ethanol synthesis – ethylene hydration and acetaldehyde reduction
- Acetic acid synthesis – methanol carbonylation
See all example routes or browse popular molecules: aspirin, caffeine, acetaminophen, vanillin, benzaldehyde, ethanol.
Who it is for
The tool is designed for organic chemistry students learning retrosynthetic analysis, researchers who want a quick first look at possible routes for a new target, and medicinal chemists screening synthetic accessibility. It is useful for exam practice, literature preparation and early route scouting.
Limitations
AI-generated routes are suggestions, not validated procedures. Reaction conditions, selectivity, protecting-group needs and safety must be checked by a qualified chemist against the primary literature before any laboratory work. Some steps may have no matching literature evidence; these are clearly marked.
Learn retrosynthesis
New to the method? Read what retrosynthesis is and how to do retrosynthesis, or browse the target catalog for example molecules such as aspirin.
FAQ
Is this retrosynthesis tool free?
Yes. You can run AI retrosynthesis for free after creating an account. Free accounts have a daily job limit; a paid membership raises the daily and monthly limits.
What is retrosynthesis?
Retrosynthesis is a problem-solving method in organic chemistry where a target molecule is worked backwards, step by step, into simpler precursors until readily available starting materials are reached.
What input does the tool accept?
You can paste a SMILES string or draw the structure in the built-in editor. The structure editor exports SMILES automatically.
How accurate are the AI-predicted routes?
Routes are generated by an AI model and are intended as starting points. Always verify reagents, conditions and selectivity against the literature before running any reaction.
How many routes can I get for one molecule?
You can request between one and five routes per job and set a time limit of up to 600 seconds for more complex targets.
Free online AI retrosynthesis tools
ChemicalTool Reaction is retrosynthesis software you can use in the browser— an online retrosynthesis tool for retrosynthesis prediction, retrosynthetic route planning, and SMILES to synthesis route search. Draw a chemical structure or paste SMILES to run AI retrosynthesis with optional library evidence.
What is retrosynthesis? How to do it
New to the method? Read what is retrosynthesis in organic chemistry and how to do retrosynthesis, or see the AI retrosynthesis tools overview. Browse the target catalog for common molecules.