Abbreviations substituent prefixes

The system of naming now used was devised by the International Union of Pure and Applied Chemistry, abbreviated IUPAC. In the IUPAC system, a chemical name has three parts prefix, parent, and suffix. The parent name tells how many carbon atoms are present in the longest continuous chain the suffix identifies what family the molecule belongs to and the prefix (if needed) specifies the location of various substituent groups attached to the parent chain ... 

Optical isomerism is when two molecules are nonsuperimposable mirror images of each other (Think of a pair of gloves. They can only stack palm to palm, not one on top of the other.) Such molecules are termed asymmetric or chiral. (Note Chiral carbons have 4 different substituents.) Two optical isomers can be distinguished in their names by the prefixes dextro- or levo- according to whether a solution of the compound rotates a beam of polarized light to the right or the left. The abbreviations d- and l- are commonly used for dextro- and levo-. A new system of naming uses R- (rectus) and S- (sinister). 

There are three different ways that two groups can be attached to a benzene ring, so a prefix— ortho, meta, or para—can be used to designate the relative position of the two substituents. Ortho, meta, and para are also abbreviated as o, m, and p, respectively. 

In disubstituted aromatic systems, the position of the second substituent with respect to the first functional group is indicated either by a number, with the first group having the 1 position, or by the prefix ortho, meta or para indicating the 2, 3 or 4 positions, respectively. These prefixes are often abbreviated to o, m orp, respectively. If a mono-substituted aromatic compound is attacked at a ring carbon that already bears a substituent, then this is called ipso attack. 

Benzene molecules bearing alkyl substituents are called alkylbenzenes. The simplest of these is methylbenzene (common name, toluene), shown in Figure 27-1 Ic. The dimethyl-benzenes are called xylenes. Three different compounds (Table 27-6) have the formula CgH4(CH3)2 (see margin). These three xylenes are constitutional isomers. In naming these (as well as other disubstituted benzenes), we use prefixes ortho- (abbreviated o-), meta- m-), or para- (p-) to refer to relative positions of substituents on the benzene ring. The ortho- prefix refers to two substituents located on adjacent carbon atoms for example, 1,2-dimethylbenzene is o-xylene. The meta- prefix identifies substituents on C atoms 1 and 3, so 1,3-dimethylbenzene is 7w-xylene. The para- prefix refers to substituents on C atoms 1 and 4, so 1,4-dimethylbenzene is p-xylene. 

The cyclic catechoylamides, in which R = (CH2)P are abbreviated as n, m, p, m-CYCAM. The sulfonated and the analogous nitro derivatives are indicated by n, m, p, m-CYCAMS and n, m, p, m-CYCAM-N02 respectively. The linear sulfonated catechoylamides are abbreviated as m, n, m-LICAMS. A prefix is added to indicate terminal N substituents... 

The relative positions of two substituents on a benzene ring can be indicated either by numbers or by the prefixes ortho, meta, and para. Adjacent substituents are called ortho, substituents separated by one carbon are called meta, and substituents located opposite one another are designatedpara. Often, only their abbreviations (o, m,p) are used in naming compounds. 

Three isomers are possible when two groups are substituted for hydrogen atoms on the benzene ring. The relative positions of the substituents are indicated by either the prefixes ortho-, meta-, para- (abbreviated 0-, m-, p-), or... 

H. Bruce Goodbrand (Xerox Research Centre of Canada) having 3,4-dimethylphenyl substituents have been abbreviated as Xy, aryl groups with para substituents are prefixed by p, tetrathiafulvalene has been abbreviated as TTF, and its tetramethyl tetraseleno analogue as TMTSF. 

Uns- unsym-) adj. Abbreviation for un-symmetrical, a prefix denoting unsyrmnet-rical disposition of substituents of organic compounds with respect to the carbon skeleton or a functional group. It is usually ignored in alphabetization of compound names. 

When two substituents are present, three isomeric structures are possible. They are designated by the prefixes ortho-, meta-, and para-, which are usually abbreviated as 0-, m-, andp-, respectively. If substituent X is attached (by convention) to carbon 1, then o-groups are on carbons 2 and 6, m-groups are on carbons 3 and 5, and p-groups are on carbon 4. ... 

Sulfonamides are effective chemotherapeutics against coccus infections. The most effective sulfonamides include iV -substituted derivatives of sulphanilamide. Derivatives of carbonic acid as well as heterocyclic rings usually serve as substituents. The other part of sulfanilic acid, H2N-C6H4-SO2-, is abbreviated as sulfe. Consequendy, the names of sulfonamides are composed of the prefix sulfa and the basic group at the S-atom. In practice, sulfonamides can be separated on all OmniPac columns, because their p/values allow anion-exchange interactions. 

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