[halcyonmind]

Hello,

I'm writing up some work on opioids and am trying to decide how to name them. Having spent a while slogging my way through the IUPAC rules I've come up with a few different ways, all are semisystematic in that they incorporate either the parent 'morphinan' or 'oripavine'. I'd really like some feedback, comments, objections, suggestions, etc. from other chemists as to what they think.

All comments very welcome; you don't need to go through checking all of the stereochem (though please do if you'd like!). Examiner quite big on conformity to conventions, which is no bad thing necessarily, so closer to IUPAC perfection, the better!

As my compounds are similar in structure to buprenorphine (http://opioids.com/buprenorphine/buprenorphine.jpg) I'll show the four different ways for that compound:

Format 1 (morphinan as substituent on butan-2-ol):
(2S)-2-[(5R,6R,7R,14S)-17-cyclopropylmethyl-4,5-epoxy-6,14-ethano-3-hydroxy-6-methoxymorphinan-7-yl]-3,3-dimethylbutan-2-ol

Format 2 (all the substituents coming off morphinan-3-ol:
(5R,6R,7R,9R,13R,14S)-17-Cyclopropylmethyl-7-[(S)-3,3-dimethyl-2-hydroxybutan-2-yl-]-4,5-epoxy-6,14-ethano-6-methoxymorphinan-3-ol

Format 3 (all the substituents coming off morphinan)
(5R,6R,7R,9R,13R,14S)-17-Cyclopropylmethyl-7-[(S)-3,3-dimethyl-2-hydroxybutan-2-yl-]-4,5-epoxy-6,14-ethano-3-hydroxy-6-methoxymorphinan

Format 4 (all substituents coming off oripavine and stereochemistry described both in absolute terms (R/S) and with reference to projection above or below the plane of the molecule (beta/alpha))
21-Cyclopropyl-7alpha-[(S)-1-hydroxy-1,2,2-trimethylpropyl]-6,14-endo-ethano-6,7,8,14-tetrahydrooripavine

[discodermolide]

The compound in the link you provided is:
(4R,4aS,6S,7R,7aR,12bS)-3-(cyclopropylmethyl)-6-(2-hydroxy-3,3-dimethylbutan-2-yl)-7-methoxy-1,2,3,4,5,6,7,7a-octahydro-4a,7-ethano-4,12-methanobenzofuro[3,2-e]isoquinolin-9-ol

according to ChemDraw.

[halcyonmind]

Thanks for the reply. Yeah, I'd rather use a semi-systematic IUPAC name as the fully systematic ones are pretty much impenetrable and give very little clue as to what is actually going on. Morphinan is an IUPAC accepted parents structure, and oripavine is a natural product that can be used as a parent structure. I'm erring on the side of using morphinan, it's just a matter of how the substituents should be described (e.g. should morphinan be a substituent group on an alcohol, or the other way around).

[discodermolide]

I would say that the morphinan should be a substituent on the alcohol.

[halcyonmind]

Thanks discodermolide - do you mean as in morphinan-3-ol or [morphinan-7-yl]-3,3-dimethylbutan-2-ol?

[discodermolide]

As in the latter, "[morphinan-7-yl]-3,3-dimethylbutan-2-ol"

[mjpam]

According the IUPAC Nomenclature for Organic Chemistry §P-41, alcohols have higher naming priority than heteranes ([fused poly]cyclic systems) of any type. In the case of buprenorphine, the morphinanyl moiety would therefore be a substituent of the alcohol.

[halcyonmind]

Brilliant, many thanks for your help