6-APDB aka 6-(2-Aminopropyl)-2,3-dihydrobenzofuran (6-APDB, 4-Desoxy-MDA, EMA-3) is a stimulant and entactogen research chemical of the phenethylamine and amphetamine classes.

6-APDB is an analogue of MDA where the heterocyclic 4-position oxygen from the 3,4-methylenedioxy ring has been replaced with a methylene bridge.

6-APDB, along with 5-APDB, was first synthesized by David E. Nichols in the early 1990s while investigating non-neurotoxic MDMA analogues

In animal studies, 6-APDB fully substitutes for MBDB.

MBDB is a closely related chemical analogue of MDMA, with the only difference between the two molecules being an ethyl group instead of a methyl group attached to the alpha carbon.MBDB was first synthesized by David E. Nichols and tested and written about by Alexander Shulgin