Alkanes systematic names

By combining the basic principles of lUPAC notation with the names of the various alkyl groups we can develop systematic names for highly branched alkanes We 11 start with the following alkane name it then increase its complexity by successively adding methyl groups at various positions... 

A single alkane may have several different names a name may be a common name or it may be a systematic name developed by a well defined set of rules The most widely used system is lUPAC nomencla ture Table 2 6 summarizes the rules for alkanes and cycloalkanes Table 2 7 gives the rules for naming alkyl groups... 

Systematic names for carboxylic acids are derived by counting the number of car bons m the longest continuous chain that includes the carboxyl group and replacing the e ending of the corresponding alkane by oic acid The first three acids m Table 19 1 methanoic (1 carbon) ethanoic (2 carbons) and octadecanoic acid (18 carbons) illus trate this point When substituents are present their locations are identified by number... 

Both common and systematic names of compounds are used throughout this volume, depending on which the Editor-in-Chief feels is most appropriate. Preparations appear in the alphabetical order of names of the compound or names of the synthetic procedures. The Chemical Abstracts indexing name for each title compound, if it differs from the title name, is given as a subtitle. Because of the major shift to new systematic nomenclature adopted by Chemical Abstracts in 1972, many common names used in the text are immediately followed by the bracketed, new names. Whenever two names are concurrently in use, the carre CChemical Abstracts name is adopted. The prefix n- is deleted from -alkanes and w-alkyls. All reported dimensions are now expressed in S st me International units. 

Simple carboxylic acids derived from open-chain alkanes are systematically named by replacing the terminal -e of the corresponding alkane name with -oic acid. The —C02H carbon atom is numbered Cl. 

One of the major organizing principles in organic chemistry is the presence of special arrangements of atoms. These so-called functional groups convey particular chemical properties. For example, a substance that contains an —OH group is called an alcohol. The systematic name of an alcohol is obtained by adding the suffix -ol to the name of the alkane with the same carbon framework. Thus, CH3 OH has the carbon framework of methane and is called methanol, whereas C2 H5 OH has the carbon framework of efhane and is called ethanol. 

The alkene series of hydrocarbons is characterized by having one double bond in the carbon chain. The characteristic formula for members of the series is C H2 . Since there must be at least two carbon atoms present to have a carbon-to-carbon double bond, the first member of this series is ethene, C2H4, also known as ethylene. Propene (propylene), C,Hh, and butene (butylene), C4HK, are the next two members of the series. Note that the systematic names of these compounds denote the number of carbon atoms in the chain with the name derived from that of the alkane having the same number of carbon atoms (Table 21-2). Note also that the characteristic ending -ene is part of the name of each of these compounds. 

Alkanes are named in a very systematic way. Review the rules for naming alkanes. 

In general, organic compounds are given systematic names by using the order prefix-parent-suffix, where prefix indicates how many branching groups are present, parent indicates how many carbons are in the longest chain and suffix indicates the name of the family. Common names as weU as systematic names are used for alkanes and their derivatives. However, it is advisable to use systematic names or the lUPAC (International Union of Pure and Applied Chemistry) nomenclature, which can be derived from a simple set of rules. 

The systematic name of an alkene originates from the name of the alkane corresponding to the longest continuous chain of carbon atoms that contains... 

In alphabetical order, the substituents are ethyl (at C-8), isopropyl at (C-4), and two methyl groups (at C-2 and C-6). The alkane is 8-ethyl-4-isopropyl-2,6-dimethyldecane. The systematic name for the isopropyl group (1-methylethyl) may also be used, and the name becomes 8-ethyl-2,6-dimethyl-4-(l-methylethyl)decane. 

The systematic names of the higher members of the homologous series of alkanes indicate the number of carbon atoms present in the chain (pentane has 5, hexane has 6,... decane has 10, and so on), but the names of the first few members are based on chemical history [methyl (1), ethyl (2), propyl (3) and butyl (4)] and one just has to leam what these represent. 

IUPAC Names Systematic names of ketones are derived by replacing the final -e in the alkane name with -one. The alkane name becomes alkanone. In open-chain ketones, we number the longest chain that includes the carbonyl carbon from the end closest to the carbonyl group, and we indicate the position of the carbonyl group by a number. In cyclic ketones, the carbonyl carbon atom is assigned the number 1. 

Systematic names for aldehydes are derived by replacing the final -e of the alkane name with -al. An aldehyde carbon is at the end of a chain, so it is number 1. If the aldehyde group is a substituent of a large unit (usually a ring), the suffix carbaldehyde is used. 

The most modem rules for the systematic naming of alkanes follow ... 

The nnsaturated hydrocarbons include the alkenes, which contain one double bond per molecule, and the alkynes, which contain one triple bond per molecnle. Their systematic names begin as the names of the corresponding alkanes do, bnt they end with -ene or -yne, respectively. The location of the multiple bond may have to be specified in the name by including the address of the mnltiple-bonded carbon atom that is closer to the end of the chain. The alkenes and alkynes are more active than the alkanes for example, they react with halogens to form halogenated hydrocarbons under mnch less severe... 

Draw the structural isomers for the alkane C6H14 and give the systematic name for each one. 

The systematic name for an aldehyde is obtained from the parent alkane by removing the final -e and adding -al. For ketones the final -e is replaced by -one, and a number indicates the position of the carbonyl group where necessary. Examples of common aldehydes and ketones are shown in Fig. 22.13. Note that since the aldehyde functional group always occurs at the end of the carbon chain, the aldehyde carbon is assigned the number 1 when substituent positions are listed in the name. 

To assign the systematic name, find the longest continuous carbon chain bonded to the amine nitrogen, and change the -e ending of the parent alkane to the snffix -amine. Then use the usual rules of nomenclature to number the chain and name the snbstituents. 

The hydrocarbons discussed so far in this chapter are referred to as saturated, because all the carbon-carbon bonds are single bonds. Hydrocarbons that have double and triple carbon-carbon bonds are referred to as unsaturated (Fig. 7.10). Ethylene (C2H4) has a double bond between its carbon atoms and is called an alkene. The simplest alkyne is acetylene (C2H2), which has a triple bond between its carbon atoms. In naming these compounds, the -ane ending of the corresponding alkane is replaced by -ene when a double bond is present and by -yne when a triple bond is present. Ethene is thus the systematic name for ethylene, and ethyne for acetylene, although we will continue to use their more common names. For any compound with a carbon backbone of four or more carbon atoms, it is necessary to specify the location of the double or triple bond. This is... 

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