Having read a short report on DMMDA-2 and its N-methyl analogues somewhere on Erowid, I thought these compounds are all pretty light with barely noticeable psychedelic activity and also far from proper empathogens comparable to MDMA. Doses weren't even comparable to those of MDA though and I wouldn't expect anything significant happening below 150mg.
I guess it's similar to some extent with MMDA and MMDA-2. MMDA doesn't seem to be much like TMA and it may be because the methylenedioxy ring forces the methylene into a fixed position which may be bad for the 3-methoxy interacting with a serine residue but mainly negative for the interaction happening between the receptor and the substituent at the para position of the aromatic ring (also cf. lophophine and mescaline). It seems to be the case here, the active dose is higher and higher dosage may mean that some secondary effects come into play and that may be why MMDA is so different from other 3,4,5-trisubstituted phenethylamines/amphetamines. Overall, there's always a drop in potency if you compare a methylenedioxy compound with its dimethoxy analogue (MMDA vs. TMA, MMDA-2 vs. TMA-2).
On the other hand methoxy and dimethoxy analogues of 6-APB might turn out to be potent psychedelics, the 3. position of benzofuran is extremely susceptible to electrophilic substitution, so we've got a hydrophobic carbon atom with a partial negative charge. I've read some horror stories about 6-APB, it's certainly capable of producing extreme anxiety and paranoia given its action both at 5-HT2A receptors and monoamine transporters. It looks like 5-methoxy group might help to both increase affinity at 5-HT2A receptors and diminish monoaminergic activity. However, the main problem with these compounds is working out the synthesis, the amount of steps and the need of sophisticated methods makes it very troublesome. It should be much easier with 6-APDB analogues and they should still be more potent than methylenedioxyamphetamines, yet probably less potent than methoxylated 6-APB's, the upside is the reduction of monoaminergic activity should be even bigger.
