Polyfunctional compounds, nomenclature

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

Many organic compounds contain more than one functional group. When one of those functional groups is halo (X-) or alkoxy (RO-), these groups are named as substituents as described in Sections 7.2 and 9.3B. To name other polyfunctional compounds, we must learn which functional group is assigned a higher priority in the rules of nomenclature. Two steps are usually needed ... 

Judging from the number of incorrect names that appear in the chemical literature, it s probably safe to say that relatively few practicing organic chemists are fully conversant with the rules of organic nomenclature. Simple hydrocarbons and monofunctional compounds present few difficulties because the basic rules for naming such compounds are logical and easy to understand. Problems, however, are often encountered with polyfunctional compounds. Whereas most chemists could correctly identify hydrocarbon 1 as 3-ethyl-2,5-dimethylheptane, rather few could correctly identify poly functional compound 2. Should we consider 2 as an ether As an ethyl ester As a ketone As an alkeae It is, of course, all four, but it has only one correct name ethyl 3-(4-methoxy-2-oxo-3-cyclohexenyl)propanoate. 

Appendix A Nomenclature of Polyfunctional Organic Compounds A-1 Appendix B Acidity Constants for Some Organic Compounds A-8 Appendix C Glossary A-10 Appendix D Answers to In-Text Problems A-30... 

A polyfunctional organic molecule can contain many different kinds of functional groups, but for nomenclature purposes, we must choose just one suffix. It s not correct to use two sufhxes. Thus, keto ester 3 must be named either as a ketone with an -one. suffix or as an ester with an -oate suffix but can t be named as an -onoate. Similarly, amino alcohol 4 must be named either as an alcohol (-ol) or as an amine i-amine) but can t properly be named as an -olamine. The only exception to this rule is in naming compounds that have double or triple bonds. For example, the unsaturated acid H2C=CHCH2C00H is 3-butenoic acid, and the acetylenic alcohol HCSCCH2CH2CH2CH2OH is 5-hexyn-l-ol. 

When silicon compounds were becoming more and more important, a gioup of chemists met to discuss the nomenclature problems involved. The purpose of the meeting is well stated in the preamble to the rules (13) which resulted from this and subsequent meetings. The purpose of the following rules is to provide one systematic and unique name for each of the simple organosilicon compounds and to guide in the selection of an accurate name for each of the more complex or polyfunctional compoimds of this nature. ... 

Rule 13. Coordination of groups in lower functionality than usual. The nomenclature of compounds involving monocoordination of bifunctional groups and the dicoordination of polyfunctional groups, etc., usually can be handled according to the rules previously given. 

---