Carboxylic acids continued nomenclature

The nomenclature for this homologous series is somewhat confused. The term PANs has been used historically to denote peroxyacyl nitrates, and this terminology continues to be used extensively in the literature, despite the lack of adherence to traditional IUPAC rules of nomenclature. Because the PANs can be considered to be mixed anhydrides of carboxylic acids and nitric acid, another suggestion (Roberts, 1990) has been peroxyacetic nitric anhydride for CH,C(0)00NO2 and peroxy carboxylic nitric anhydrides for the whole class of compounds. Although it does not follow the IUPAC rules, it would be consistent with the widespread use of the name PAN but also reflect the structure more accurately. Table 6.20 shows the structures and commonly used names of some PANs that have been observed in the atmosphere and/or in laboratory studies. 

The IUPAC nomenclature for carboxylic acids uses the name of the alkane that corresponds to the longest continuous chain of carbon atoms. The final -e in the alkane name is replaced by the suffix -ok acid. The chain is numbered, starting with the carboxyl... 

The lUPAC nomenclature is based on the longest continuous chain (alkane, alkene, or alkyne based) that contains the carboxyl carbon (the -COOH unit). As with aldehydes, the carbon of the COOH group is always at one terminus of the chain and must receive the lowest possible number (1), which is omitted from the name. The suffix for carboxylic acids is oic acid, with the word acid separated from the first part of the name. As with aldehydes and ketones, the carboxyl unit is higher in priority than an alkene or alkyne. Compound 38 is an eight-carbon acid with an alkane backbone, so it is octanoic acid (note the short notation for the carboxyl group). Substituents are numbered relative to the carbonyl carbon of the COOH unit, so 39 is 2,2-dimethyl-5-phenyloctanoic acid. In a similar manner, 40 is named 16-chloro-4-ethylheptadecanoic acid. 

Figure 14.7 Cyclooxygenase action. Prostaglandin nomenclature Prostaglandins are abbreviated PG followed by a letter indicating the type of functionality present at positions 8-12 and 15 the number subscript refers to the number of double bonds and the Greek letter designates the orientation of the extra hydroxyl group on the ring. Numbering always starts at the carboxylic acid (1 position) and continues around the molecule for the entire 20-carbon atoms.

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