orthonym.rules.bridged_fused_pin.fusion_names#

Note

Internal API. Names and behaviour may change between releases.

Fusion names of the carbocyclic parents the tables do not hold: two or three ortho-fused rings whose name has exactly two components, numbered by OPSIN’s reading of it.

(the Blue Book): “‘ortho-Fused’ or ‘ortho- and peri-fused’ polycyclic ring

systems with the maximum number of noncumulative double bonds (mancude) 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).” This module builds that name for one class and declines everything else:

  • two rings of sizes m < n, n >= 7: ‘<prefix>[n]annulene’. (:11968): “Monocyclic parent components are named as [n]annulenes where n represent the number of carbon atoms. The series starts at n = 7”; (c) (:12234) “A component containing the larger ring at the first point of difference when comparing rings in order of decreasing size” makes the larger ring the parent; (:13970) “the omission is also recommended when the fused ring system is made of two monocyclic hydrocarbons” (‘1H-cyclopenta[8]annulene (PIN)’:13974, ‘benzo[8]annulene (PIN)’:19564);

  • three rings in a row X-Y-Z where X-Y or Y-Z is a two-ring hydrocarbon component (pentalene, indene, azulene, naphthalene, heptalene, octalene: and the

    polyalenes): (b) (:12163) “a component containing the greater number

    of rings”, then (c), choose the parent; the third ring is the attached component, cited with the letter of the parent side it is fused to: (:11911) “each peripheral side of the parent component (including sides whose locants are distinguished by letters, for example, 2a,3a) using the italic letters a, b, c, etc., beginning with a for the side numbered ‘1,2’… To the letter as early in the alphabet as possible that denotes the side where the fusion occurs are prefixed, if necessary, the numbers”; the numbers are omitted, (:13970) “numerical and/or letter locants are omitted in fused ring systems with only first-order monocyclic attached hydrocarbon components, ‘benzo’, and those described in “ (‘benzo[a]tetracene (PIN)’:13972; ‘4,7-methanocyclopenta[a]indene (PIN)’:19829).

Prefixes, (:12000): “Monocyclic hydrocarbon prefixes for attached components other than ‘benzo’ are formed by dropping ‘ne’ from the name of the appropriate saturated monocyclic hydrocarbon…. There is no upper ring-size limit to this criterion.” The final ‘o’/’a’ is kept Note:11909). (:23710): “Fusion nomenclature gives preferred IUPAC names only to compounds having at least two rings of at least five or more members.”

Declined: heteroatoms, three components, four or more rings, peri-fusion (an atom in three rings), two equal rings (the polyalenes are table names), a skeleton the tables name, and any name OPSIN 2.9.0 cannot read back to the same skeleton.

orthonym.rules.bridged_fused_pin.fusion_names.two_component_name(key_mol)#

The fusion name (no indicated hydrogen) of the carbocyclic skeleton key_mol (an element-aware all-single-bond graph, parents._key_of), or None outside the class of the module docstring. A skeleton the parent tables name has a retained, systematic or Blue Book name, which (:11903) puts before any fusion name: declined.

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

(SMILES, $_AV locants) of OPSIN 2.9.0’s reading of name (a mancude system with an odd number of atoms needs an indicated hydrogen): the first of the forms _IH_FORMS that OPSIN reads and RDKit parses decides, because an indicated hydrogen moves no skeleton atom, so if its atom count is not n_atoms no other form’s is. None when that count differs or no form is read. A call OPSIN could not answer raises validation.opsin_roundtrip.OpsinUnavailable, which the cache does not keep.