Replacement prefixes compounds

For branching compounds, the parent structure is the longest continuous chain present in the compound. Consider the compound to have been derived from this structure by replacement of hydrogen by various alkyl groups. Arabic number prefixes indicate the carbon to which the alkyl group is attached. Start numbering at whichever end of the parent structure that results in the lowest-numbered locants. The arable prefixes are listed in numerical sequence, separated from each other by commas and from the remainder of the name by a hyphen. 

Substitution means the replacement of one or more hydrogen atoms in a given compound by some other kind of atom or group of atoms, functional or nonfunctional. In substitutive nomenclature, each substituent is cited as either a prefix or a suffix to the name of the parent (or substituting radical) to which it is attached the latter is denoted the parent compound (or parent group if a radical). 

Azoxy Compounds. Where the position of the azoxy oxygen atom is unknown or immaterial, the compound is named in accordance with azo rules, with the affix azo replaced by azoxy. When the position of the azoxy oxygen atom in an unsymmetrical compound is designated, a prefix NNO- or ONN- is used. When both the groups attached to the azoxy radical are cited in the name of the compound, the prefix NNO- specifies that the second of these two groups is attached directly... 

Halogen Derivatives. Using substitutive nomenclature, names are formed by adding prefixes listed in Table 1.8 to the name of the parent compound. The prefix perhalo- implies the replacement of all hydrogen atoms by the particular halogen atoms. 

The prefix sila- designates replacement of carbon by silicon in replacement nomenclature. Prefix names for radicals are formed analogously to those for the corresponding carbon-containing compounds. Thus silyl is used for SiH3—, silyene for —SiH2—, silylidyne for —SiH<, as well as trily, tetrayl, and so on for free valences(s) on ring structures. 

Sulfonium Compounds. Sulfonium compounds of the type R R R S X are named by citing in alphabetical order the radical names followed by -sulfonium and the name of the anion. For heterocyclic compounds, -ium is added to the name of the ring system. Replacement of > CH by sulfonium sulfur is denoted by the prefix thionia-, and the name of the anion is added at the end. 

Chemists frequently work with measurements that are very large or very small. A mole, for example, contains 602,213,670,000,000,000,000,000 particles, and some analytical techniques can detect as little as 0.000000000000001 g of a compound. For simplicity, we express these measurements using scientific notation thus, a mole contains 6.0221367 X 10 particles, and the stated mass is 1 X 10 g. Sometimes it is preferable to express measurements without the exponential term, replacing it with a prefix. A mass of 1 X 10 g is the same as 1 femtogram. Table 2.3 lists other common prefixes. 

Griess (1860) coined the prefix diazo for the nitrosation product of an aromatic amine, because he assumed that two nitrogen atoms replaced two hydrogen atoms of the parent aromatic compound. On the other hand, azobenzene received its name on the basis of the C H N ratio 6 5 1, indicating the replacement of one hydrogen by one nitrogen atom. 

For example, substitution can be made on an oxygen atom in the case of esters and ethers. It is characterised by the symbol O, which is placed after the locant. The compound prefix deoxy- is composed of the prefixes de-, meaning without in subtractive nomenclature, and oxy-, to indicate the subtraction of an oxy group from an -OH group C-O-H C-H. Such an operation is needed when an -OH group is replaced by another group, such as an amino group. 

The prefix thio- indicates that sulfur is present, usually as a replacement for one or more oxygen atoms in a compound whose name is familiar. For example, in thiosulfuric acid, one 0 atom of sulfuric acid has been replaced by an S atom in thiocyanic acid, the only 0 atom of cyanic acid has been replaced in thioar-senic acid, all of the O atoms of arsenic acid have been replaced by S. The rules of naming do not normally show how many 0 atoms are replaced. HSCN is placed in Table 8-3 because of the many similarities between oxygen and sulfur. 

Two systems (246,247) will be discussed in this subsection. The nomenclature of these compounds, as of other borazaromatics, has been a point of controversy. Whereas the authors in this field generally followed the procedure of naming these compounds after the isoconjugate parent aromatic hydrocarbon with prefixes like bora and aza indicating the replacement of a methine group by these atoms, in Chemical Abstracts the principal names are derived by reference to the azaborine system. In this Section and in Section... 

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