Ketones

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Basic IUPAC Organic Nomenclature

Ketones

Nomenclature	Formula	3D structure
Functional class name = alkyl alkyl ketone Substituent suffix = -one e.g. propan-2-one Substituent prefix = oxo-

The root name is based on the longest chain including the carbonyl group.
The chain is numbered so as to give the ketone carbonyl the lowest possible number.
The ketone suffix is appended after the hydrocarbon suffix minus the "e" : e.g. -ane + -one = -anone or -ene + one = -enone etc.

Functional group is a ketone, therefore suffix = -one
Hydrocarbon structure is an alkane therefore -ane
The longest continuous chain is C3 therefore root = prop
The ketone group locant 2-

propan-2-one or 2-propanone

CH₃C(=O)CH₃

Functional group is a ketone, therefore suffix = -one
Hydrocarbon structure is an alkane therefore -ane
The longest continuous chain is C5 therefore root = pent
The first point of difference rule requires numbering from the right as drawn to make the ketone group locant 2-

pentan-2-one or 2-pentanone

ketone

CH₃CH₂CH₂C(=O)CH₃

©Dr. Ian Hunt, Department of Chemistry