[Arctic-Nation]

Sup guys & gals, I've got a problem most chemists dread to solve: constructing more-or-less correct names for some compounds. This is not for a test or exam, no bonus points are to be had, all anyone's getting is a pat on the back, a warm feeling in the gut and a nagging doubt in the brain for having spent time on this instead of something useful.

I've gone through relevant CAS and IUPAC (the Blue Book) rulesets, but while they manage to explain a lot, they fail in explaining how to combine substituents with multiply fused ring systems. On top of that, my class of compounds doesn't have any official nomenclature yet (carbahelicenes have, heterahelicenes do not, except for Balaban nomenclature, which no one uses so I'm not bothering with it).

I've attached the relevant images, so here goes: compound 0 is commonly known as tetrathia[7]helicene, or more elaborately, 3,6,9,12-tetrathia[7]helicene. This is the basis from which we start.
The names I've come up with are:
Bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene 1
Ethyl bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene-9-carboxylate 2
1-methyl-pyrrolo-2,5-dione[3,4-j]bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene 3

Now, this last one is most certainly wrong, but I'm unsure as to how go further from here. Anyone with any experience in the matter?

[discodermolide]

Sup guys & gals, I've got a problem most chemists dread to solve: constructing more-or-less correct names for some compounds. This is not for a test or exam, no bonus points are to be had, all anyone's getting is a pat on the back, a warm feeling in the gut and a nagging doubt in the brain for having spent time on this instead of something useful.

I've gone through relevant CAS and IUPAC (the Blue Book) rulesets, but while they manage to explain a lot, they fail in explaining how to combine substituents with multiply fused ring systems. On top of that, my class of compounds doesn't have any official nomenclature yet (carbahelicenes have, heterahelicenes do not, except for Balaban nomenclature, which no one uses so I'm not bothering with it).

I've attached the relevant images, so here goes: compound 0 is commonly known as tetrathia[7]helicene, or more elaborately, 3,6,9,12-tetrathia[7]helicene. This is the basis from which we start.
The names I've come up with are:
Bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene 1
Ethyl bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene-9-carboxylate 2
1-methyl-pyrrolo-2,5-dione[3,4-j]bis(4,5-bis(octyloxy)benzo)[1,2-e:1’,2’-o]tetrathia[7]helicene 3

Now, this last one is most certainly wrong, but I'm unsure as to how go further from here. Anyone with any experience in the matter?

According to ChemDraw compound 3 has the following name, assuming linear alkyl chains

7-methyl-2,3,11,12-tetrakis(octyloxy)-6H-thieno[3'',2'':3',4']naphtho[2',1':4,5]thieno[2,3-e]thieno[3'',2'':3',4']naphtho[2',1':4,5]thieno[3,2-g]isoindole-6,8(7H)-dione

[Arctic-Nation]

Yeah, it's exactly that kind of stuff I was looking to avoid. ACS reviewers suggested we base our names on naphthalene. No one working on helicenes would dare to write down an abomination like that. Besides, an indole with non-standard numbering as parent compound? That can't be right.

OK, maybe this sounds a bit negatively. I do appreciate the effort, but it's not really the kind of answer I'm looking for.

Maybe I'll make the question easier. I haven't found a rule or anything, but if there is a choice, do nitrogen-containing rings always take priority? In that case, I could write down the name as (helicene)indole-2,5-dione and be done with it.

[orgopete]

I have several opinions here. The first, I expect you have already thought of, "Really, you want a name for it?" There is a point at which the structure is far better than a name, so structure 37 is more sensible.

The second is about nomenclature itself. For any of us "older" chemists, we have seen any number of nomenclature systems. When I was teaching, I rationalized the only real value to IUPAC nomenclature was to introduce systematic nomenclature. In that, it was easier to predict names than valeric or caproic acid. However, most naming is a combination of names, e.g., 4,4-dimethylcholesterol. Although cholesterol is a common name, it is easier to learn than to decipher an IUPAC name. The substituents would follow systematic nomenclature rules the same as found in IUPAC rules.

The names given are rather complicated and I'd have to review the naming for the …[1,2-e:1’,2’-o]… part of the name. In that sense, I would consider fluffing the basic ring system and call it something like a dibenzotetrathia[7]helicene and give it a number. I'd pick up the helicene numbering and assign the substituents.

For compound 3, I'd probably go with a dicarboximide name rather than a pyrrole. A dicarboximide is a substituent while pyrrolo… is part of a heterocyclic system. Just my preference. If you were to ask the point of the name is to transfer information, then a simple test would be to ask anyone to draw the structure from the name. If they cannot do it, of what value is the name? Here, I think my naming suggestion, while not perfect would come close to what is in common use, a mix of common and systematic names. If you were to explain the numbering of the helicene derivative you have, then adding substituents should be understandable, which I would hope was the whole point of the exercise.