Ketones

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Introductory 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 C5 therefore root = pent
The first point of difference rule requires numbering from the left as drawn to make the ketone group locant 2-

2-pentanone or pentan-2-one

CH₃CH₂CH₂C(=O)CH₃

©Dr. Ian Hunt, Department of Chemistry