IUPAC Nomenclature for heterocyclic compounds

In 1957, the IUPAC Commission on Nomenclature of Organic Chemistry codified this extension of the Hantzsch-Widman system as part of its rules for the nomenclature of organic chemistry.

The heteroatoms to which the system applied were specified and certain exceptions and modifications were noted in order to avoid formation of names identical with some already in use for entirely different compounds.


Names for saturated six-membered rings without nitrogen, but containing silicon, germanium, tin, or lead, are excluded (ref. lc) because of names such as silane and disilane for acyclic hydrides (refs. 11 and 12). Although the same problem occurs with the analogous boron rings, they were not excluded; instead the stem “-inane” was used in place of “-ane” (ref. ld). Although not codified in the IUPAC Organic Nomenclature Rules, this stem change and modified prefixes such as “germana-” rather than “germa-”, have been used to avoid this problem with other saturated six-membered  rings, Names for six-membered rings that contain phosphorus, arsenic, or antimony require a change in the prefix for denoting the heteroatom because of names such as arsine and diphosphine for acyclic hydrides (ref. le). These prefix  modifications were fully documented for the unsaturated rings in the 1957 Organic Rules (ref. Sb), but their use for saturated rings was noted only in the third edition of the Sections A and B Rules (ref. lOc). Even a modified prefix is not enough for saturated six-membered phosphorus rings; the stem “-inane’ instead of “-ane” is also needed to avoid the name phosphorane used for PH5.





For further reading, click on link full text of IUPAC Nomenclature of heterocyclic compounds

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