Priority function

Alternative names are shown in some cases this should emphasize that there is often no unique correct name. Sometimes, it can be advantageous to bend the rules a little so as to provide a neat name rather than a fully systematic one. Typically, this might mean adopting a lower priority functional group as the suffix name. It is important to view nomenclature as a means of conveying an acceptable unambiguous stmc-ture rather than a rather meaningless scholastic exercise. Other examples will occur in subsequent chapters, and specialized aspects, e.g. heterocyclic nomenclature, will be treated in more detail at the appropriate time (see Chapter 11). Stereochemical descriptors are omitted here, but will be discussed under stereochemistry (see Sections 3.4.2 and 3.4.3). 

Cyano-6-hydroxy-4-heptenal (The aldehyde is the highest-priority functional group, so the OH and the CN must be denoted by their group prefixes.)... 

The —OH functional group is named as a hydroxy substituent when it appears on a structure with a higher-priority functional group or when the structure is too difficult to name as a simple alcohol. 

A ketone or aldehyde group can also be named as a substituent on a molecule with a higher priority functional group as its root. A ketone or aldehyde carbonyl is named by the prefix oxo- if it is included as part of the longest chain in the root name. When an aldehyde —CHO group is a substituent and not part of the longest chain, it is named by the prefix formyl. Carboxylic acids frequently contain ketone or aldehyde groups named as substituents. 

Number the carbon chain to give the lower number to the highest priority functional group, and then follow all other rules of nomenclature. Examples are shown in Figure B.1. 

Polyfunctional compounds that contain C-C double and triple bonds have characteristic suffixes to identify them, as shown in Table B.2. The higher priority functional group is assigned the lower number. 

Name as a derivative of benzoic acid since COOH is the higher priority functional group. 

Step 1. Find the highest priority functional group. Determine and name the longest continuous carbon chain that includes this group. 

Step 2. Number the chain so that the highest priority functional group is assigned the lower number. (The number T is often omitted when there is no confusion about where the group must be. Aldehydes and carboxylic acids must be at the first carbon of a chain, so a "1" is rarely used with those functional groups.)... 

Step 4. If the molecule includes Group A functional groups, replace the last "e" with the suffix of the highest priority functional group, and include its position number just before the name of the highest priority functional group. 

Substituents and functional groups are indicated in the usual ways. Spiro ring systems are always numbered smaller before larger, and numbered in such a way as to give the highest priority functional group the lower position number. 

Name the highest priority functional group with a suffix (acid > aldehyde > ketone > alcohol > amine) and the others with prefixes. 

The timely detection of outbreaks at the regional and national level is a priority function of communicable disease surveillance systems. In the process of implementing its IHR [4], WHO included the requirement for member states to maintain an adequate core capacity to detect and respond to significant public health threats. This requires that member states develop effective early-warning systems and strengthen their investigation and response capabilities [24, 25],... 

The compound is usually drawn so that the main carbon skeleton is vertical and the highest priority functional group is at the top of the vertical line. 

Once an action in a functional diagnosis group has been activated, further actions within the functional area will be blocked for a pre-defined dormancy period. The dormancy period allows the operator to address other, possibly lower priority, functional areas. 

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