Ring Systems Generic

Consider generic ring systems which are extensionally described, i.e., their... 

Turning now to the extensionally described generic ring systems, there are additional complexities. First, the ring description should not require the exhaustive generation of all of the specific forms of the class. Secondly, it should not depend on the orientation or form of definition of the structure. The example of Figure 13 underlines these points. 

Note 1 The polymer class name (generic name) describes the most appropriate type of functional group or heterocyclic ring system. 

Two intriguing examples of this class of compound involve ring systems in which one boron atom of a borazine ring is replaced by the isoelectronic units HC or C , as represented by the generic carbocation A or the carbene B. 

Saturated hydrocarbons also occur in petroleum in cyclic form, and will have generic molecular formulas of the form CnH2n (if monocyclic). These cycloparaffins are referred to as naphthenes in the petroleum industry and occur primarily as five, six, and seven-membered rings, with and without alkyl substituents. They also occasionally occur as various combinations of two of these ring systems linked or fused together, in which case their molecular formulas become of the form CnH2n-2 (Eq 18.4). 

FIGURE 3.7 Example generic carbon ring systems for saturated and unsaturated steroids of Cj7 to Cjj with the systematic nomenclature stem names. 

---