For researchers and companies

Retrosynthesis software, free with an account

Draw a target and Athanor’s Resolvere I model plans routes back to starting materials you can buy, with sourced hazards for every compound along the way. It runs in the same editor you draw in, with a free arbastro account.

An illustration of how it looks in the app. The real results are below.

Routes it found for common drugs

Each of these drugs can simply be bought, so the search’s first answer is to buy it. Shown here is its second: the first route that makes the drug, from compounds in stock.

paracetamol

1 step · score 0.67

in stockin stockAmide coupling
Step confidence 67%

lidocaine

1 step · score 0.78

in stockin stockN-alkylation
Step confidence 78%

atenolol

1 step · score 0.85

in stockin stock
Step confidence 85%

propranolol

1 step · score 0.94

in stockin stock
Step confidence 94%

omeprazole

2 steps · score 0.94

Step 1
in stockin stock
Step confidence 99.9%
Step 2
in stockin stock
Step confidence 94%

sildenafil

4 steps · score 0.38

Step 1
in stockin stockAmide coupling
Step confidence 69%
Step 2
in stock
Step confidence 86%
Step 3
in stockin stock
Step confidence 86%
Step 4
in stockin stockSulfonamide formation
Step confidence 74%

A step’s confidence is Resolvere’s for that disconnection, and a route’s score combines its steps; neither is a measured chance of success. Run on November 9, 2026 with Resolvere I 1.1 (search 1.1.0). Every structure on this page was screened against chemical weapons and controlled-substance lists before it was published.

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