2
Introduction
exists, particularly in the domain of parent structures, a plethora of trivial
names thought to be indispensable for various reasons. These trivial
names usually tell us nothing about the constitution of the compounds
they represent, nor can they be derived logically. However, as they are often
the starting points of a whole nomenclatural subsystem (e. g.: the fused
polycycles), we simply have to memorise as large a number as possible; this
will be facilitated by collective tables at the end of the book.
The following procedure is generally adopted for assigning a systematic
name to a given compound or for deriving a constitutional/structural formula from a given name:
1. Determine the compound class in question (e. g.: hydrocarbon, heterocycle, carboxylic acid, ketone, halogen derivative, etc., Section 2.2.1,
Table 7).
2. Determine the parent structure and define as (possibly further substituted) substituents all other constitutional or nomenclatorial elements
present (Chapter O.
3. As one and the same compound can exhibit the characteristics of more
than one compound class and may also be a combination of several
parent substructures, seniorities must be laid down, i. e., rules allowing
the assignment of priorities.
4. Define which type of nomenclature should be applied, or ascertain
which one has been used in a given name. (The IUPAC rules still permit
alternative naming possibilities which sometimes overlap with each
other, Section 2.2.) It must be noted here that in the domain of substitutive nomenclature - which is always to be preferred - certain traditional
class names are no longer considered at all in naming the pertinent
individual species, e.g.: ether ----t alkoxyalkane.
5. The constitutional or nomenclatorial elements separated according to
step 3 are individually named (or assigned to partial formulae) and
then provided with appropriate locants (numerals, letters) and markers
(enclosing marks, hyphens, primes, etc.).
6. Finally, the substituent prefixes, infixes, and suffixes are ordered according to specific rules and then inserted into the name of the parent
structure by prefixing them with the appropriate locants.
7. If needed, isotopic modifiers (Section 6.6) and stereochemical descriptors (Section 6.7) must be added.
In connection with the terms "priority" and "seniority" two fundamental
principles of systematic nomenclature can be stated:
a) as far as is feasible, lowest locants possible (numerals, letters) should be
applied; i.e. when there is a choice, that constitutional or nomenclatorial element is to be preferred which bears the smallest locant.
Introduction
exists, particularly in the domain of parent structures, a plethora of trivial
names thought to be indispensable for various reasons. These trivial
names usually tell us nothing about the constitution of the compounds
they represent, nor can they be derived logically. However, as they are often
the starting points of a whole nomenclatural subsystem (e. g.: the fused
polycycles), we simply have to memorise as large a number as possible; this
will be facilitated by collective tables at the end of the book.
The following procedure is generally adopted for assigning a systematic
name to a given compound or for deriving a constitutional/structural formula from a given name:
1. Determine the compound class in question (e. g.: hydrocarbon, heterocycle, carboxylic acid, ketone, halogen derivative, etc., Section 2.2.1,
Table 7).
2. Determine the parent structure and define as (possibly further substituted) substituents all other constitutional or nomenclatorial elements
present (Chapter O.
3. As one and the same compound can exhibit the characteristics of more
than one compound class and may also be a combination of several
parent substructures, seniorities must be laid down, i. e., rules allowing
the assignment of priorities.
4. Define which type of nomenclature should be applied, or ascertain
which one has been used in a given name. (The IUPAC rules still permit
alternative naming possibilities which sometimes overlap with each
other, Section 2.2.) It must be noted here that in the domain of substitutive nomenclature - which is always to be preferred - certain traditional
class names are no longer considered at all in naming the pertinent
individual species, e.g.: ether ----t alkoxyalkane.
5. The constitutional or nomenclatorial elements separated according to
step 3 are individually named (or assigned to partial formulae) and
then provided with appropriate locants (numerals, letters) and markers
(enclosing marks, hyphens, primes, etc.).
6. Finally, the substituent prefixes, infixes, and suffixes are ordered according to specific rules and then inserted into the name of the parent
structure by prefixing them with the appropriate locants.
7. If needed, isotopic modifiers (Section 6.6) and stereochemical descriptors (Section 6.7) must be added.
In connection with the terms "priority" and "seniority" two fundamental
principles of systematic nomenclature can be stated:
a) as far as is feasible, lowest locants possible (numerals, letters) should be
applied; i.e. when there is a choice, that constitutional or nomenclatorial element is to be preferred which bears the smallest locant.