Stereoisomers subclasses

The 1,2-diinethylcyclopropanes are members of a subclass of stereoisomers called cis-trans isomers. The prefixes cis- (Latin "on the same side") and tmns-(Latin "across") are used to distinguish between them. Cis-trans isomerism is a common occurrence in substituted cycloalkanes. 

Stereoisomers isomers of identical constitution but differing in the arrangement of then-atoms in space. Subclasses include constitutional isomers, enantiomers, and diastereomers. 

The glucose 6-phosphate thus formed can enter glycolysis or another pathway such as the pentose phosphate pathway, described in Section 14.5. Phosphoglucomutase employs essentially the same mechanism as phos-phoglycerate mutase (p. 531). The general name mu-tase is given to enzymes that catalyze the transfer of a functional group from one position to another in the same molecule. Mutases are a subclass of isomerases, enzymes that interconvert stereoisomers or structural or positional isomers (see Table 6-3). 

At a later date the structure of the V(MeDta)4 also was determined (242). Two independent molecules in the asymmetric unit show geometries consistent with the two different stereoisomers belonging to the dodecahedral subclasses IdiPid 42m) and Vd(C2 - 2). 

We may divide the large number of known cases (and the even greater number of hypothetical cases) of inorganic isomerism into two very broad classes (1) position isomers having the same sets of atoms but different sets of bonds (as is the ease with ethyl alcohol and dimethyl ether) and (2) stereoisomers having the same atoms, the same sets of. bonds, but differing somehow in the orientation of these bonds. Werner and many workers after him recognized a number of subclasses of position isomerisms. 

Two molecules with the same sequence of atoms but with different spatial arrangement of atoms are called stereoisomers. They thus differ from constitutional isomers which have different sequences of atoms for the same overall chemical formula. Consequently, constitutional and stereo isomers are subclasses of isomers which are molecules with the same overall chemical formula, but differing in structure. An isomer may be either a constitutional or a stereo isomer it can never be simultaneously both. 

When two or more compounds have the same composition but a different arrangement of atoms, we call them isomers, (Section 2.9) Here we consider two main kinds of isomers in coordination compounds structural isomers (which have different bonds) and stereoisomers (which have the same bonds but different ways in which the ligands occupy the space around the metal center). Each of these classes also has subclasses, as shown in A FIGURE 2ai9. 

Understanding the three-dimensional properties of organic molecules is an essential part of organic chemistry. The experiments in this chapter are designed to provide an introduction to stereoisomers. Such isomers have molecular skeletons that are identical, but they differ in the three-dimensional orientation of their atoms in space. The two broad subclasses of stereoisomers that are of importance in organic chemistry are conformational isomers and configurational isomers. 

Stereoisomers (Section 4.2) are compounds whose atoms are connected in the same order but with a different spatial arrangement. Among the kinds of stereoisomers we ve seen are enantiomers, diastereo-mers, and cis-trans isomers of cycloalkanes. Actually, cis-trans isomers are just a subclass of diastereomers because they are non-mirror-image stereoisomers ... 

As we have just seen, 2-butene exists in cis- and tm s-forms—the methyl groups may be on the same side (cis) or opposite sides (trans) of the double bond. These are usually described as geometric isomers and are distinct from the structural isomers discussed in the last chapter. All the same bonds are present, but the directional property of the bonds means that they are distinct compounds with different chemical and physical properties. This is a subclass of stereoisomers, which we will discuss in more detail in Chapter 7. The terms cis and trans are adequate... 

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