Parent names

Like aldehydes ketone functions take precedence over alcohol functions double bonds halogens and alkyl groups m determining the parent name and direction of numbering Aldehydes outrank ketones however and a compound that contains both an aldehyde and a ketone carbonyl group is named as an aldehyde In such cases the carbonyl oxy gen of the ketone is considered an 0x0 substituent on the mam chain... 

Systematic names formed by applying the principles of substitutive nomenclature are single words except for compounds named as acids. First one selects the parent compound, and thus the suffix, from the characteristic group listed earliest in Table 1.7. All remaining functional groups are handled as prefixes that precede, in alphabetical order, the parent name. Two examples may be helpful ... 

Listed in order of decreasing priority for citation as principal group or parent name. 

Prefixes and Affixes. Prefixes are arranged alphabetically and placed before the parent name multiplying affixes, if necessary, are inserted and do not alter the alphabetical order already attained. The parent name includes any syllables denoting a change of ring member or relating to the structure of a carbon chain. Nondetachable parts of parent names include... 

Compounds of the type R NH—OR are named (1) as alkoxyamino derivatives of compound R H, (2) as A, 0-substituted hydroxylamines, (3) as alkoxyamines (even if R is hydrogen), or (4) by the prefix aminooxy- when another substituent has priority for parent name. Examples of each type are... 

Peroxides. Compounds of the type R—O—OH are named (1) by placing the name of the radical R before the word hydroperoxide or (2) by use of the prefix hydroperoxy- when another parent name has higher priority. For example, C2H5OOH is ethyl hydroperoxide. 

Formula Parent name Substitutive prefix ending... 

When a chain or ring system is composed entirely of alternating silicon and oxygen atoms, the parent name siloxane is used with a multiplying affix to denote the number of silicon atoms present. The parent name silazane implies alternating silicon and nitrogen atoms multiplying affixes denote the number of silicon atoms present. 

Hansa Yellows, 1, 334 5, 299 Hantzsch synthesis, 2, 87-88 1,4-dihydropyridine, 2, 482 thiazoles, 6, 294-299 A -thiazolines, 6, 314 Hantzsch-Widman names parent names, 1, 35 stem suffixes, 1, 12 Hantzsch-Widman system nomenclature, 1, 11-12 Hardeners in photography... 

Paraxanthine—see Xanthine, 1,7-dimethyl-Parent name nomenclature, 1, 35 Parham cycloalkylation in chroman synthesis, 3, 783 Paromomycins as pharmaceuticals, 1, 154 Partial charge transfer from donor to acceptor stacks, 1, 350 Pasteurellosis... 

In general, replacement prefixes should not be added to heterocyclic parent names, because of the resulting multiplicity of possible synonyms. For example, structure (27) should not be named 2,3,4,6-tetraazaindole or 3,4,6-triazaindazole without very good... 

Individual compound names are derived from parent names in the usual way by specifying the degree of hydrogenation (with -ene, -yne, hydro- and dehydro-) e.g. 84 and 85) and the substituents (with appropriate prefixes and suffixes). However, there are other ways in which parent names can be modified. Changes in stereochemistry can be indicated by use of the prefix ent- (meaning a reversal in configuration of all asymmetric centres) or by... 

As mentioned above, it is usually most convenient to employ as parent structure a skeleton from which all functional substituents have been removed. However, there are many substituted parent names in common use, either with or without implied stereochemistry (see examples 102-106). 

Substitution (see Seetion 1.02.9.1.1) is the formal proeedure most widely applied in modifying parent names. Indeed, the general term substitutive nomenclature is often used to describe the system of nomenclature in which substitution is the main operation. A fundamental concept of this system is that of the principal characteristic group . 

The locant is preferably placed directly before the -yl suffix, but may be placed before the parent name if no ambiguity results (in those cases where the radical name is substantially altered from that of the parent, the locant is conventionally placed in front of the name of... 

It is common for names of simple heterocyclic carbonyl derivatives to be contracted, with loss of the -ine ending of the parent name, e.g. pyridone, quinolone, acridone, pyrrolidone, thiazolidone. 

Find the longest continuous carbon chain in the molecule, and use that as the parent name. This molecule has a chain of eight carbons--octane—with two methyl substituents. (You have to turn corners to see it.) Numbering from the end nearer the first ntelhvl substituent indicates that the methvls are al C2 and C6... 

This is the reverse of Worked Example 3.2 and uses a reverse strategy. Look at the parent name (hexane), and draw its carbon structure. 

Step 3 Write the full name. Number the substituents according to their positions in the chain, and list them alphabetically. Indicate the position of the double bond by giving the number of the first alkene carbon and placing that number directly before the parent name. If more than one double bond is present, indicate the position of each and use one of the suffixes -diene, -triene, and so on. 

We should also note that 1UPAC changed their naming recommendations in 1993 to place the locant indicating the position of the double bond immediately before the -ene suffix rather than before the parent name but-2-ene rather than 2-butene, for instance. This change has not been widely accepted by the chemical community, however, so we ll stay with the older but more commonly used names. Be aware, though, that you may occasionally encounter the newer system. 

Monosubstituled benzenes are systematically named in the same manner as other hydrocarbons, with -benzene as the parent name. Thus, C6H5Br is bromo-benzene, C6H5NC>2 is nitrobenzene, and Q5H5CH2GII2CH3 is propylbenzene. 

Note in the second and third examples showm that -phenol and -toluene are used as the parent names rather than -benzene. Any of the monosubstituted aromatic compounds shown in Table 15.1 can serve as a parent name, with the principal substituent (-OH in phenol or -CHj in toluene) attached to Cl on the ring. 

Rule 1 Select the longest carbon chain containing the hydroxy) group, and derive the parent name by replacing the -e ending of the corresponding alkane with -ol. The -c is deleted to prevent the occurrence of two adjacent vowels propanol rather than propaneol, for example. 

Phenols are named as described previously for aromatic compounds according to the rules discussed in Section 15.1. Note that -phenol is used as the parent name rather than -benzene. 

Ketones are named by replacing the terminal -e of the corresponding alkane name with -one. The parent chain is the longest one that contains the ketone group, and the numbering begins at the end nearer the carbonyl carbon. As with alkenes (Section 6.3) and alcohols (Section 17.1), the locant is placed before the parent name in older rules but before the suffix in newer IUPAC recommendations. For example ... 

Unsymmetrically substituted secondary and tertiary amines are named as iV-substituted primary amines. The largest alkyl group is chosen as the parent name, and the other alkyl groups are N-substituents on the parent (jY because they re attached to nitrogen). 

Heterocyclic amines—compounds in which the nitrogen atom occurs as part of a ring—are also common, and each different heterocyclic ring system has its own parent name. The heterocyclic nitrogen atom is always numbered as position 1. 

As further examples, compounds 10 and 11 are both keto acids and mus be named as acids, but the parent name in 10 is that of a ring system (cyclo hexanecarboxylic acid) and the parent name in 11 is that of an open chair (propanoic acid). The full names are frrt/ s-2-(3-oxopropyl)cyclohexane carboxylic acid (10) and 3-(2-oxocyclohexyl)propanoic acid (11). 

Partial esters are named via insertion of the term hydrogen (separated by spaces) between the ester radical name and the parent name. For example, CH3P(OH)OC2H5 is named ethyl hydrogen methylphosphonite or ethyl hydrogen methanephosphonite. 

Systematic names for individual dialdoses are formed from the systematic stem name for the corresponding aldose (see 2-Carb-8.2), but with the ending odialdose instead of ose , and the appropriate configurational prefix (Chart I). A choice between the two possible aldose parent names is made on the basis of 2-Carb-2.2.2. 

Part II consists entirely of systematic names of specific compounds according to Chemical Abstracts nomenclature (see the Index Guide in Chemical Abstracts, Volume 76, 1972). Each compound is listed under the parent name as it would appear in Chemical Abstracts, and each entry from Volumes 56 through 59 is followed by the registry number in brackets. Entries from Volumes 58 and 59 are, for the most part, taken from the appendices which follow the procedures. When the Chemical Abstracts name differs in Collective Indices 8 and 9, both names have been included. Some compounds in the appendices of this volume have been omitted from the index in accord with the guidelines given for Part I. 

Locate the longest continuous chain of carbon atoms this chain determines the parent name for the alkane. 

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