Athanor by arbastro
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How to predict where substitution goes on a ring

Select an aromatic structure and choose Object › Chemistry › Where substitution goes. Expected positions are marked in full, minor ones in outline, with the reason for each.

Steps

  1. Select a substituted benzene, for example anisole.

  2. Choose Main menu › Object › Chemistry › Where substitution goes.

  3. Each ring position is marked: a filled dot is expected, an outline is minor. The list names each group and what it directs, then gives every position with its reason.

    Anisole: ortho and para to the alkoxy group expected, meta unlikely.Anisole: ortho and para to the alkoxy group expected, meta unlikely.

Note

These are the directing rules taught for benzene, not a trained model. Each group votes for ortho/para or for meta by its strength, the votes add, and a position between two groups is crowded. Expected positions often come as an ortho/para mixture whose ratio depends on the electrophile and on crowding.

Reactions and arrowsHow to draw a reaction schemeDraw or insert the reactants, press W and drag a reaction arrow after them, write the conditions above it with the Text tool, then add the products after the arrow. Or press / and type the whole reaction as reaction SMILES.Atoms, bonds and ringsHow to highlight functional groupsChoose View › Show functional groups. Each group is shaded in its own color and named in a legend, such as Ester, Carboxylic acid and Arene for aspirin. Choose it again to hide them.

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Last updated Nov 12, 2026