TP-3 Semisystematic Porphyrin Names

TP-3 Semisystematic porphyrin names
TP-3.1 Semisystematic names in substituted porphyrins
TP-3.2 Subtractive nomenclature
TP-3.3 Combinations of substitutive and subtractive operations
TP-3.4 Additional ring formation
TP-3.5 Skeletal replacement of substituted porphyrins

TP-3.1. Semisystematic Names For Substituted Porphyrins. As an alternative to a systematic name based on the porphyrin ring nucleus, compounds closely related to the trivially named porphyrins listed in Rule TP-2, Table 2 and Table 3, but differing in that one or more hydrogen atoms have been replaced (substituted) by one or more other atoms or groups, may be named semisystematically based on one of the trivially named parent porphyrins. Prefixes, and/or a suffix of the new substituents are combined with the trivial name of the parent porphyrin.

Note 1. See TP-1.7 for generation of systematic names.

Note 2. Precise guidelines for naming modified or substituted side chains of trivially named natural products are needed. In general, chain lengthening of substituent groups by substitution of hydrogen atoms by alkyl groups is less preferred than removal of the entire side group and the addition of the new group. See TP-3.2 for subtractive nomenclature.

Note 3. See IUPAC Rule C-10.3.

The functional group of highest priority, not implied in the trivial parent name, may be expressed as a suffix. The remaining substitutents not implied by the trivial name are expressed by prefixes. Locants and multiplying prefixes are added as appropiate, and the prefixes arranged in alphabetical order.

When there is a choice among trivially named parent porphyrins, the one with the highest possible rank number in Table 2 is preferred. However a porphyrin of lower rank may be selected where special emphasis is desired.

Functional derivatives such as esters and lactones are named similarly and in accord with the rules for organic nomenclature.

Note See Rule C-4.6 and C-4.7. See also TP-3.4.

Examples:

1.

Semisystematic: 15-Methylrhodoporphyrin Systematic: 18-Carboxy-8,13-diethyl-3,7,12,17,20-      -pentamethylporphyrin-2-propionic acid Fischer: Chloroporphyrin e4

Note 1. Not phylloporphyrin-13-carboxylic acid. Rhodoporphyrin has a higher rank number than phylloporphyrin.

Note 2. See TP-1.7 for generation of systematic names.

2.

Semisystematic: Rhodoporphyrin-15-acetic acid Systematic: 18-Carboxy-20-(carboxymethyl)-8,13-diethyl-      -3,7,12,17-tetramethylporphyrin-2-propionic acid Fischer: Chloroporphyrin e6

Note 1. Note that in contrast to regular practices of substitutive nomenclature that the propionic principal group is unexpressed. In these rules a subordinate group may be cited as a suffix. Compare IUPAC Rule C-10.3.

Note 2. For systematic numbering see TP-1.1 and TP-1.7

3.

Semisystematic: Phytoporphyrin-132-carboxylic acid Systematic: 22-Carboxy-7,12-diethyl-21,22-dihydro-      -3,8,13,17-tetramethyl-21-oxocyclopenta[at]porphyrin-      -18-propionic acid Fischer: Pheoporphyrin a5

Note if it is necessary to specify the absolute stereochemistry of this molecule, it should be indicated by R or S in accord with TP-0.3.

4.

Semisystematic: 151,151-Dihydroxyrhodoporphyrin-15-acetic acid      δ-lactone Systematic:18-Carboxy-20-(carboxydihydroxymethyl)-8,13-diethyl-      -3,7,12,17-tetramethylporphyrin-2-propionic acid &delta-lactone Fischer: Pheoporphyrin a7

Note 1. Note that in contrast to regular practices of substitutive nomenclature that the propionic principal group is unexpressed. In these rules a subordinate group may be cited as a suffix. Compare IUPAC Rule C-10.3.

Note 2. If it is necessary to specify the absolute stereochemistry of this molecule, it should be indicated by R or S in accord with TP-0.3.

Note 3. For systematic numbering see TP-1.1 and TP-1.7.

Note 4. Alternatively a name based on ring fusion principles could be formed, but see footnote d, TP-1.3.

5.

Semisystematic: Phylloporphyrin-151-oic acid Systematic: 20-Carboxy-8,13-diethyl-3,7,12,17-      -tetramethylporphyrin-2-propionic acid Fischer: γ-Carboxypyrroporphyrin

Note Not Pyrroporphyrin-15-carboxylic acid. Phylloporphyrin ranks higher than pyrroporphyrin in Table 2.

6.		Semisystematic: 3-Formy1-8-vinyldeuteroporphyrin Systematic: 8-Formyl-3,7,12,17-tetramethyl-13-      -vinylporphyrin-2,18-dipropionic acid Fischer: Chlorocruoroporphyrin or      Spirographisporphyrin
7.		Semisystematic: 71-oxophylloporphyrin Systematic: 8,13-Diethyl-12-formyl-3,7,17,20-      -tetramethylporphyrin-2-propionic acid Fischer: Rhodinporphyrin g3

TP-3.2. Subtractive Nomenclature. The prefix "de" followed by the name of a substituent group is used to denote the removal of that substituent from the semisystematic parent porphyrin and its replacement by the appropriate amount of hydrogen as in organic nomenclature. These prefixes combined with a multiplicative prefix denote the loss of a corresponding number of substituents or atoms. "Dehydro" denotes the loss of one hydrogen atom. The "de" prefix is nondetachable from the name of the substituent group to which it refers. Simple subtractive prefixes are alphabetized disregarding the multiplying prefixes, di, tri, tetra, penta, etc. When there is a choice, as low locants as possible are selected for the subtractive prefixes as in systematic substitutive nomenclature.

Note 1. Further development of guidelines for choice of the trivially named parent porphyrin, its numbering, and limits of application of these operations is needed.

Note 2. See IUPAC Rule C-41.

Note 3. See IUPAC provisional Rules F-4.10 and F-4.13.

Note 4. See IUPAC Rule C-15.11(d) and (e).

Example:

Semisystematic: 3,8-Dideethyletioporphyrin III Systematic: 3,7-Diethyl-2,8,12,17-tetramethylporphyrin Fischer: Deuteroetioporphyrin IX

Note See TP-1.7 for formation of the systematic name.

TP-3.3. Combinations of Substitutive and Subtractive Operations. The subtractive operations of TP-3.2 may be combined with the operations of substitution of TP-3.1 to denote the removal of a group or atom from a position in the parent porphyrin and subsequent substitution at any position. The subtractive prefixes are alphabetized among the substitutive prefixes. As low locants as possible are selected for substitutive and subtractive prefixes considered together in one series. If this is not decisive, then the numbering is chosen that assigns the lowest locant to the first cited substituent or subtractive prefix. When a porphyrin structure can be considered as a derivative of two or more trivially named parent porphyrins listed in Tables 2 and Tables 3, and shown in Appendix 1, the name that requires the fewest number of subtractive and substitutive operations combined is preferred. If this is not decisive, then the name that requires the smaller number of subtractive prefixes is preferred.

Example:

Semisystematic: 7-Demethyl-7-(methoxycarbonyl)rhodoporphyrin-     -15-acetic acid 13-methyl ester Systematic: 20-(Carboxymethyl)-8,13-diethyl-12,18,bis(methoxycarbonyl)-     -3,7,17-trimethylporphyrin-2-propionic acid Fischer: Rhodinporphyrin 88     (as one of its dimethyl esters)

Note Alternate formats for naming this diester should be considered such as 7-carboxy-7-demethylrhodoporphyrin-15-acetic acid 7,13-dimethyl ester, or 13-methyl 7-demethyl-7-(methoxycarbonyl)rhodoporphyrin-15-acetate. Present IUPAC nomenclature rules are not definitive in this respect.

TP-3.4. Additional ring formation. Compounds closely related to the trivially named porphyrins of Rule TP-2 but in which an additional ring has been formed by means of a direct link between two atoms of the parent structure are named by prefixing "cyclo" preceded by the locants of the positions joined by the new bond. Alternatively such compounds may be named according to the provisions for fused rings in Rule TP-1.3.

Note See IUPAC provisional Rule F-4.1.

Examples

1.		Semisystematic: 151,172-Cyclophylloporphyrin-     -13-carboxylic acid Systematic: 8,13-Diethyl-22,23-dihydro-3,7,12,17-tetramethyl-     -21H-benzo[at]porphyrin-22,18-dicarboxylic acid Fischer: Neoporphyrin 4
2.		Semisystematic: 132,15-Cycloetioporphyrin III, or     172-Decarboxy-131-deoxophytoporphyrin Systematic: 7,12,18-Triethyl-21,22-dihydro-3,8,13,17-     -tetramethylcyclopenta[at]porphyrin Fischer: Deoxophylloerythroetioporphyrin

Note 1. If it is necessary to specify the absolute stereochemistry of this molecule, it should be by R or S according to TP-0.3.

Note 2. See TP-1.3 for the systematic name and numbering of the fundamental ring.

TP-3.5. Skeletal Replacement of Substituted Porphyrins. Trivially named porphyrins in which one or more of the atoms in the porphyrin ring nucleus have been replaced by atoms of other elements are named by prefixing to the trivial name, the appropriate locants with corresponding multiplicative and replacement prefixes. Where there is a choice due to the symmetry of substituents, the replacing atoms are numbered in line with IUPAC Rule B-4.

Note See. TP-1.4 and TP-1.5 for systematic names and numbering of skeletally replaced fundamental porphyrin systems.

Example:

Semisystematic: 5-Azaprotoporphyrin Systematic: 2,7,12,18-Tetramethyl-3,8-divinyl-     -5-azaporphyrin-13,17-dipropionic acid