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Aspirin Retrosynthesis

Aspirin (acetylsalicylic acid, ASA) is one of the world's most widely used pharmaceuticals. Its classical synthesis involves esterification of salicylic acid with acetic anhydride.

Target

Aspirin: CC(=O)Oc1ccccc1C(=O)O

import renkin

result = renkin.find_routes(
    smiles="CC(=O)Oc1ccccc1C(=O)O",
    depth=5,
    max_routes=5,
)

for route in result["routes"]:
    print(f"Route (depth {route['depth']}):")
    for step in route["steps"]:
        print(f"  {' + '.join(step['precursors'])}  [{step['rule']}]")

Expected Routes

RENKIN finds two main disconnection strategies:

Route 1: Ester cleavage (depth 1)

CC(=O)Oc1ccccc1C(=O)O
    → CC(=O)O + Oc1ccccc1C(=O)O
    [ester_cleavage]
  • Acetic acid (CC(=O)O) — available from stock
  • Salicylic acid (Oc1ccccc1C(=O)O) — available from stock

This corresponds to the reverse of the Fischer esterification / Einhorn procedure.

Route 2: Acyl chloride route (depth 1)

CC(=O)Oc1ccccc1C(=O)O
    → CC(=O)Cl + Oc1ccccc1C(=O)O
    [aryl_ether_retro / friedel_crafts variant]
  • Acetyl chloride (CC(=O)Cl) — available from stock
  • Salicylic acid (Oc1ccccc1C(=O)O) — available from stock

This corresponds to the classical industrial synthesis using acetyl chloride.

Try It

→ Open in Playground

Enter CC(=O)Oc1ccccc1C(=O)O in the SMILES field to try interactively.