5-APDB

5-(2-Aminopropyl)-2,3-dihydrobenzofuran (5-APDB, 3-Desoxy-MDA, EMA-4) is a putative entactogen drug of the phenethylamine and amphetamine classes. It is an analogue of the MDA where the heterocyclic 3-position oxygen from the 3,4-methylenedioxy ring has been replaced by a methylene group. 6-APDB is an anlogue of 5-APDB where the 4-position oxygen has been replaced by a methylene instead. 5-APDB was developed by a team led by David E. Nichols at Purdue University as part of their research into non-neurotoxic analogues of MDMA.

In animal studies, 5-APDB's effects generalize most closely to non-stimulant MDMA analogues such as MBDB and MMAI, while producing no substitution for LSD or amphetamine. In vitro studies show that 5-APDB acts as a highly selective serotonin releasing agent (SSRA), with IC50 values of 130 nM, 7,089 nM, and 3,238 nM for inhibiting the reuptake of serotonin, dopamine, and norepinephrine, respectively. In contrast, 6-APDB is more balanced on the three monoamine neurotransmitters and acts more similarly to MDA and MDMA. Anecdotal reports from human users suggest that 5-APDB produces mild empathy but with relatively little euphoria and is accompanied by sedation.

Methoxy-substituted analogues of 5-APDB and 6-APDB have also been made and substituted for DOM in animal tests, although they were around 10x less potent than DOM.