Naming Aldehydes and Ketones Ketones named by replacing terminal -e of corresponding alkane name with -one Parent chain is longest chain containing ketone group Numbering begins at end of chain nearer the carbonyl carbon O= CH3CH2CCH2CH2CH3 CH3CH=CHCH2CCH3 CH3CH2CCH2CCH3 1°2341 5 6 6°54321 6°54321 Hexan-3-one Hex-4-en-2-one Hexane-2,4-dione (Old:3-Hexanone) (Old:4-Hexen-2-one) (Old:2,4-Hexanedione) Ketones named by replacing terminal –e of corresponding alkane name with –one ▪ Parent chain is longest chain containing ketone group ▪ Numbering begins at end of chain nearer the carbonyl carbon Naming Aldehydes and Ketones