From the first reference, note that the ligand with the HIGHEST affinity is the N-cyclopropylmethyl-N-methyl derivative.
But the latter doesn't detail ANY examples with a tertiary amine. Neither does it examine the enantiomers. Is it possible that both are equally active but I would argue unlikely.
Like ciramidol, dimetadine, trans-BDPC, lefetamine, doxicopamine and a few others, this class possesses a benzylamine moiety. All of those are most active with an N,N-dimethyl moiety and the chiral examples all demonstrate the (R) enantiomer to be the active, it seems highly likely that:
(R)-2,2-dimethyl-3-(dimethylamino)-3-phenyl-N-(2-phenylethyl)propanamide (as yet not recorded as having been synthesized) is likely to be the most potent AGONIST.
It's worth noting that Table 9-12 on page 417 of 'Opiates' by Lenz et all demonstrates that N-desmethylmethadone (ED50 53.9( is an order of magnitude lower than methadone (ED50 5.2) a ratio common to the metabolites of many opioids containing an N,N-dimethyl moiety.
Sadly the relative affinity data for N,N-dimethyl containing opioids and their N-desmethyl metabolites isn't available due to the time when they were discovered, it isn't possible to confirm if demethylation reduces affinity OR reduces agonist activity OR both of those variables.
While the derivatives bearing a meta -OH on the B-ring demonstrate higher affinity, it seems that like the m-OH homologues of BDPC, they will demonstrate antagonist activity. It's worth noting that homologues lacking said m-OH are significantly simpler to produce.
Given that this compound has never been synthesized (or at least their is no record of such), it would not be controlled by an law. It's structurally unrelated to any other opioid.
