PhI-4.5. Numbering of Heterophane Parent Hydrides with Respect to Heteroatoms Described by Skeletal Replacement ("a") Nomenclature

PhI-4.5. Numbering of Heterophane Parent Hydrides with Respect to Heteroatoms Described by Skeletal Replacement ("a") Nomenclature
References for this section

When there is a choice for numbering heterocyclic amplificants named by skeletal replacement nomenclature or for numbering simplified phane skeletons in which skeletal replacement has taken place, the following criteria are applied, in the order given, until a decision is reached.

PhI-4.5.1. Lowest locants are assigned to heteroatoms considered together without regard to the nature of the heteroatom, first with regard to the set of primary locants of the heteroatoms, i.e., the locants of the simplified skeleton (without including any superscript numbers), and then, if these locants are identical, with regard to the set of complete heteroatom locants, which includes the primary locant and superscript numbers (see also PhI-3.3.3).

Example 26.

Step 1: 1(2,5)-thiophena-5(1,3)-cyclohexanacyclooctaphane

Step 2: 2,7-dithia-1(2,5)-thiophena-5(1,3)-cyclohexanacyclooctaphane (26a)

not 3,8-dithia-1(2,5)-thiophena-5(1,3)-cyclohexanacyclooctaphane (26b)

[the locant set for the heteroatoms in 26a, "2,7", is lower than the locant set in 26b,"3,8".]

Example 27.

Step 1: 1,6(1,3)-dicyclohexanacyclotridecaphane

Step 2: 5-oxa-7-thia-2,8,13-triaza-1,6(1,3)-dicyclohexanacyclotridecaphane (27a)

not 2-oxa-13-thia-5,7,12-triaza-1,6(1,3)-dicyclohexanacyclotridecaphane (27b)

(The locant set for all heteroatoms in 27a, "2,5,7,8,13", cited for comparison in ascending order, is lower than the locant set in 27b, "2,5,7,12,13".)

Example 28.

Step 1: 1,5(1,5)-dicycloundecana-3(1,3)-benzenacycloheptaphane

Step 2: 2,7-dioxa-1⁸,5²-diaza-1,5(1,5)-dicycloundecana-3(1,3)-benzenacycloheptaphane

not 4,6-dioxa-1²,5⁸-diaza-1,5(1,5)-dicycloundecana-3(1,3)-benzenacycloheptaphane

(The primary locant set in the correct name, cited for comparison in ascending order, "1,2,5,7", is lower than the locant set "1,4,5,6".)

Example 29.

Step 1: 3(2,5)-furana-1,5(1,6)-dicyclododecanacycloundecaphane

Step 2: 1²,5³-dioxa-3(2,5)-furana-1,5(1,6)-dicyclododecanacycloundecaphane

not 1³,5²-dioxa-3(2,5)-furana-1,5(1,6)-dicyclododecanacycloundcaphane

(The primary heteroatom locant sets are the same, "1,3,5"; the composite heteroatom locant set 1²,5³ is lower than the locant set 1³,5².)

PhI-4.5.2. Lowest locants are assigned to heteroatoms considered in the order of their priority, i.e., O > S > Se > Te > N > P > As > Sb > Bi > Si > Ge > Sn > Pb > B (refs. 1m, 2m, 19a), first with regard to the set of primary locants of the heteroatoms, i.e., the locants of the simplified skeleton (without including any superscript numbers), and then, if these locants are identical, with regard to the set of complete heteroatom locants, which includes the primary locant and superscript numbers (see also PhI-3.3.3).

Example 30.

Step 1: 1,4(1,3)-dicyclohexanacyclohexaphane

Step 2: 2-thia-6-phospha-1,4(1,3)-dicyclohexanacyclohexaphane

not 6-thia-2-phospha-1,4(1,3)-dicyclohexanacyclohexaphane

(Since thia is preferred to phospha in the element priority order, it must be given the lower locant.)

Example 31.

Step 1: 3(2,5)-furana-1,5(1,5)-dicyclotetradecanacyclododecaphane

Step 2: 2,4,6,12-tetraoxa-1²-thia-5²-aza-3(2,5)-furana-1,5(1,5)-diyclotetradecanacyclododecaphane

not 2,4,6,12-tetraoxa-5²-thia-1²-aza-3(2,5)-furana-1,5(1,5)-diyclotetradecanacyclododecaphane

(Application of PhI-4.5.1 reveals that both the primary locant sets and the locant sets including the composite locants for the heteroatoms without regard to the kind of heteroatom are the same for both names, 1,2,4,5,6,12 and 1²,2,4,5²,6,12, respectively. Since the primary locants for the "oxa" prefixes are also the same, the primary locant for the next most senior heteroatom, "thia", is compared and in the correct name the primary locant "1" is lower than the primary locant "5".)

Example 32.

Step 1: 1,6(1,4)-dibicyclo[2.2.1]heptanacyclodecaphane

Step 2: 1²,1⁷,6³,7,10-pentaoxa-2,5,6⁷-trithia-1,6(1,4)-dibicyclo[2.2.1]heptanacyclodecaphane (32a)

not 1³,1⁷,2,5,6²-pentaoxa-6⁷,7,10-trithia-1,6(1,4)-dibicyclo[2.2.1]heptanacyclodecaphane (32c)

not 1³,6²,6⁷,7,10-pentaoxa-1⁷,2,5-trithia-1,6(1,4)-dibicyclo[2.2.1]heptanacyclodecaphane (32d)

(Application of PhI-4.5.1 eliminates names 32c and 32d because, although the primary locant sets for the heteratoms, without regard to the kind of heteroatom, for 32a and 32b are the same, 1,1,2,5,6,6,7,10, the locant sets including composite locants for both, 1²,1⁷,2,5,6³,6⁷,7,10, are lower than the corresponding locant set for 32c and 32d, 1³,1⁷,2,5,6²,6⁷,7,10. Then, according to PhI-4.5.2, the name for 32a is correct because its set of primary locants for "oxa", 1,1,6,7,10, is lower than the set of primary locants for "oxa" in 32b, 1,2,5,6,6.)

Example 33.

Step 1: 1,9(1,8)-dicyclotetradecanacyclohexadecaphane

Step 2: 1³,2,8,9³,10,16-hexaoxa-1¹³,9¹³-ditha-1,9(1,8)-dicyclotetradecanacyclohexadecaphane (33a)

not 1¹³,2,8,9¹³,10,16-hexaoxa-1³,9³-ditha-1,9(1,8)-dicyclotetradecanacyclohexadecaphane (33b)

(In both names the primary locant sets and the locant sets including the composite locants for the heteroatoms without regard to the kind of heteroatom, 1,1,2,8,9,9,10,16 and 1³,1¹³,2,8,9³,9¹³,10,16, respectively, are the same. The primary locant sets for the senior prefix "oxa" are also the same in both cases, 1,2,8,9,10,16, but for the locant sets including composite locants, the locant set for the prefix "oxa" in 33a, 1³,2,8,9³,10,16, is lower than the corresponding locant set for "oxa" in 33b, 1¹³,2,8,9¹³,10,16.)

(1) International Union of Pure and Applied Chemistry. Organic Chemistry Division. Commission on Nomenclature of Organic Chemistry, A Guide to IUPAC Nomenclature of Organic Compounds, Recommendations 1993, R. Panico, W. H. Powell and Jean-Claude Richer (Senior Editor), Blackwell Scientific Publications, Oxford, 1993, 190 pp. (a) R-1.2.2.1, p. 23; R-2.3.3.2, p. 43; R-5.5.4.3, p. 95. (b) R-0.2.4.2, p. 17. (c) R-2.4.2.1, especially footnote 29, p. 49. (d) R-2.4.3, p. 51. (e) R-2.4.2, pp. 49-51. (f) R-2.4.3.1, pp. 51-2. (g) R-2.4.3.2, p. 52. (h) R-0.1.8, p. 10. (i) R-2.3.1.2, p. 39; R-2.3.3 (in part), pp. 40-4; R-2.4.1, pp. 44-9. (j) R-2.4.1.2, p. 46. (k) R-2.3.1.1, p. 39; R-2.3.3 (in part), pp. 40-4. (m) R-9.3, p.182. (n) R-2.3.3.2, p. 43. (o) R-2.4.2, pp. 49-51.

(2) International Union of Pure and Applied Chemistry. Organic Chemistry Division. Commission on Nomenclature of Organic Chemistry, Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, 1979 Edition, J. Rigaudy and S. P. Klesney eds., Pergamon Press, Oxford 1979, 559 pp. (a) B-4, pp. 68-70; C-0.6, pp. 123-7; D-1.6, pp. 334-6; D-5.17, p. 388; D-6.71, pp. 419-20. (b) A-2.6, p. 10, footnote; C-13.11(e), p. 99, footnote; D-4.14, p. 374, footnote. (c) A-31.1, p. 31, especially its footnote. (d) Spiro hydrocarbons, p. 37, especially its footnote. (e) A-31.1 and A-31.2, p. 31; A-32, pp. 32-4. (f) A-41.1 and A-41.2, p. 38. (g) A-41.6, p. 39. (h) C-16.11, p. 108. (i) A-11.3, pp. 16-17 (benzene); A-21 and A-22, pp. 20-7; B-2 (in part) and B-3, pp. 55-68. (j) A-34, pp. 35-7; B-15 (in part), pp. 75-6. (k)A-11.1, p. 16; B-2.12 (in part), pp. 62-3; D-4.21, p. 375; D-4.51 (in part), pp. 378-9. (m) Appendix, Table I, pp. 459-60. (n) B-14 (in part), p. 75. (o) B-10.1, p. 72.

(19) International Union of Pure and Applied Chemistry. Organic Chemistry Division. Commission on Nomenclature of Organic Chemistry, "Revision of the Extended Hantzsch-Widman System of Nomenclature for Heteromonocycles (Recommendations 1982)", Pure Appl. Chem. 1983, 55, 409-16. (a) Table 1, p. 413.

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