Methyl isopropyl ketone, naming

Ethyl isopropyl ketone may be alternatively named 2-methyl-3-pentanone. Its longest continuous chain has five carbons. The carbonyl carbon is C-3 irrespective of the direction in which the chain is numbered, and so we choose the direction that gives the lower number to the position that bears the methyl group. 

The common names are methyl propyl ketone for compound V, diethyl ketone for compound VI, and isopropyl methyl ketone for compound VII. 

Aromatic ketones are often named by treating the benzene ring as a phenyl group, as in isopropyl phenyl ketone (Fig. 16.12). A few can be named through the lUPAC system in which the framework Ph—C=0 is indicated by the term ophenone and the remainder of the molecule designated by one of the alternative names in Rgure 16.12. Thus, diphenyl ketone is benzophenone, methyl phenyl ketone is acetophenone, ethyl phenyl ketone is propiophenone, and phenyl propyl ketone is butyrophenone (Fig. 16.12). 

Ketones may also be named using functional class lUPAC nomenclature by citing the two groups attached to the carbonyl m alphabetical order followed by the word ketone Thus 3 methyl 2 butanone (substitutive) becomes isopropyl methyl ketone (functional class)... 

As an example of the co-existence of systematic, semi-systematic and trivial names, we could look at the monoterpenoid ketone, carvone. Carvone occurs in both enantiomeric forms in nature, the laevo-form in spearmint and the dextro-form in caraway. The trivial name carvone is derived from the Latin name for caraway, Carum carvi. The basic carbon skeleton is that of l-isopropyl-4-methylcyclohexane. This skeleton is very common in nature and is particularly important in the genus Mentha, which includes various types of mint, since it forms the backbone of most of the important components of mint oils. The skeleton has therefore been given the name p-menthane and the numbering system used for it is shown in Figure 1.3. Therefore, any of the following names may be used to describe the same molecule carvone, p-mentha-1,8-dien-6-one and 1 -methyl-4-(l-methylethenyl)cyclohex-l-ene-6-one. To classify it, we could say it was an unsaturated ketone of the /7-menthane family of monoterpenoids. 

Synonyms/Trade Names 2-Acetyl propane. Isopropyl methyl ketone. 3-Methyl-2-butanone. 3-Methyl butan-2-one. MIPK ... 

N.B. This ketone gives a stable complex with boron trifluoride [8172], named 2,2-difluor-4-isopropyl-5,7-dimethoxy-6-methyl-l-oxa-3-oxonia-2-boratanaph-thalin (in German in the paper) (m.p. 141-142°) [8171], oil [8189] m.p. 56° [8171] ... 

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