orthonym.rules.bridged_fused_pin.hetero_fusion#

Note

Internal API. Names and behaviour may change between releases.

Two-component fusion names with a heterocyclic component, and benzo names, for the ortho-fused parents no table holds (slice S2c-1), numbered by OPSIN’s reading of the name.

(the Blue Book): ring systems “that have no accepted retained or systematic

name described in sections and are named by prefixing to the name of a component ring or ring system (the parent component) designations of the other component(s) (attached components).” The name is formed in two stages:

  1. Components (fusion_components): the monocycles and the one-component polycyclic names of the tables, retained names used whole. The parent component is the senior component of the whole skeleton by (a)-(j) (:12137), every component that occurs counted (the book’s own reasons rank components that are not in the final name: carbazole over quinoxaline:12232, acridine over phenanthridine:12386). The rest of the skeleton must be one component, fused to the parent by one bond, or two components of which one is a benzene ring that the second stage merges.

  2. Benzo names: (:11815) “If the initial identified preferred components for naming a fused ring system include an isolated benzo component (i.e. not forming part of a component with a retained name such as quinoline or anthracene) ortho-fused to a heteromonocyclic component of five or more members, these two components are treated together as a one-component unit”; (:13437) “They may be treated as a parent component or an attached component depending on the order of seniority… However, this approach is not used if it disrupts a multiparent system… or the use of multiplicative prefixes”;:13443 ‘thieno[3,2-f][2,1]benzothiazole (PIN) (2,1-benzothiazole is senior to 1-benzothiophene)’,:13449 ‘[1,2]benzoxazolo[6,5-g]quinoline (PIN)’,:13459 ‘4H-[1,4]thiazino[2,3-g]quinoline (PIN) (the retained name quinoline must be used)’,:13463 ‘6H-dibenzo[b,d]pyran (PIN) (not 6H-benzo[c][1]benzopyran…)’. A whole skeleton made of one benzene ring and one heteromonocycle of five or more members is a benzo name.

A tetravalent fusion atom (an atom with four ring bonds in three rings, one of which shares a bond with each of the others) is named as an ordinary ortho-fusion: (:14007) “Both terminal fusion atom locants for ortho-fusion must be cited even if one is a fusion atom” (‘naphtho[1,8a-b]azirine (PIN)’ :14011), so the saxitoxin skeleton is ‘pyrrolo[1,2-c]purine’ (fusion_components.ortho_rings; the pyrrole is fused on side c, N3-C4, of purine, whose C4 is a fusion atom). Its numbering is OPSIN’s, as every numbering here, and fusion_components.periphery_numbering_ok is the one check the engine makes on it (compute_fused_numbering has no tetravalent atom in its grid).

Declined (other slices): multiparent names;:13453 ‘benzo[1,2-b:4,5-c’]difuran (PIN) (not furo[3,4-f][1]benzofuran…)’,:41087 ‘benzo[1,2-c:4,5-c’]dipyrrole (not pyrrolo[3,4-f]isoindole…)’), multiplied attached components:13467), three or more components, peri-fusion and interior atoms, a heteroatom that needs the lambda-convention, a skeleton the tables name, and any name OPSIN 2.9.0 cannot read back to the same skeleton.

The descriptor: (:11911) the parent sides lettered “a for the side numbered ‘1,2’, b for ‘2,3’… To the letter as early in the alphabet as possible that denotes the side where the fusion occurs are prefixed, if necessary, the numbers of the positions of attachment of the other component. These numbers are chosen to be as low as is consistent with the numbering of the compound and their order conforms to the direction of lettering of the parent component”;

(:11917) brackets, no space or hyphen around them; (:13970) the numbers

are omitted for ‘benzo’ and the monocyclic hydrocarbon prefixes (‘benzo[g]quinoline (PIN)’ :13978); (:14007) both terminal locants, a fusion atom’s included (‘naphtho[1,8a-b]azirine (PIN)’:14011); Note (:11909) no elision; (:23710) at least two rings of five or more members.

orthonym.rules.bridged_fused_pin.hetero_fusion.rule_name(key_mol)#

The name the two stages give the skeleton key_mol (an element-aware all-single-bond graph, parents._key_of), before the tables are asked: a benzo name for one benzene ring and one heteromonocycle, a two-component fusion name otherwise, or None outside the class of the module docstring.

orthonym.rules.bridged_fused_pin.hetero_fusion.hetero_component_name(key_mol)#

rule_name for a skeleton no parent table names:11903 puts every retained, systematic or Blue Book name first).

orthonym.rules.bridged_fused_pin.hetero_fusion.opsin_structure(name, n_atoms)#

fusion_names.opsin_structure with the indicated-hydrogen forms widened: a heterocyclic parent may need one indicated hydrogen at any position or two (‘4H,5H-pyrano[4,3-d][1,2,3]dioxathiine’,:21239). The first form OPSIN reads decides, as there.