Free IUPAC Name Generator: Structure to Name

Get the IUPAC name from a photo of the structure

Upload a photo of the skeletal formula — from a textbook page, a problem set, or your own handwritten drawing — and the generator reads the structure from the image. You can also paste a SMILES string or describe the structure in words.

Whichever input you use, the result comes with the naming steps set out: the parent chain identified, the substituents located and numbered, the prefixes ordered alphabetically, and the final name assembled. Seeing the steps is the point — the same rules apply to the next structure on your problem set.

Get Accurate Chemical Names with the IUPAC Generator

Organic nomenclature is a set of rules applied in a fixed order, not a table you can look a molecule up in. Most of the marks in a naming question sit in that order — which chain you picked, which end you numbered from, which group outranked the others — and that is what this tool writes out alongside the name.

It covers the compound classes an organic course actually sets: alkanes, alkenes and alkynes, alcohols, aldehydes and ketones, carboxylic acids and their derivatives, ethers, amines, and substituted aromatic rings. Bridged polycyclic frameworks and heavily decorated natural products are where any naming tool is weakest, and the answer says so rather than covering it up.

The name is only half the output. Underneath it you get the parent chain that was chosen, the direction the chain was numbered in, the locant assigned to each substituent, and the alphabetical order they were listed in — the four places a hand-written name usually goes wrong. Check that working against your course notes before you hand anything in.

• A photo of the textbook page or your own drawing
• A SMILES string pasted straight into the box
• The connectivity described in plain words
• The naming steps written out under the name

Worked naming examples

Four short structures, each one showing a different rule doing the work. Read the name, then read the reason next to it — the reason is what transfers to the next question.

• CH3-CH2-CH(CH3)-CH3 is 2-methylbutane. The longest chain is four carbons, so the parent is butane, and numbering from the nearer end puts the methyl branch on carbon 2 rather than carbon 3.
• CH3-CH(OH)-CH2-CH3 is butan-2-ol. The hydroxyl group outranks the chain, so it takes the suffix and the lowest locant; the position of the suffix is written into the name, not left implied.
• CH3-CH=CH-CH2-CH3 is pent-2-ene. Five carbons make it a pentene, and the double bond is cited by the lower-numbered carbon it starts from.
• A benzene ring with a methyl and a nitro group at positions 1 and 3 is 1-methyl-3-nitrobenzene. Both substituents are prefixes, so they are listed alphabetically — methyl before nitro — and the ring is numbered to give the lowest set of locants.

Names like acetone or toluene are common names, not systematic ones. Where a common name is the one your course uses, the answer gives both.