Salvinorin B methoxymethyl ether, also known as 2-O-methoxymethylsalvinorin B (2-MMSB) is a semisynthetic analogue of the natural product salvinorin A which is used in scientific research.
It has a longer duration of action of around 2 to 3hours, compared to less than 30minutes for salvinorin A, and has increased affinity and potency at the ú-opioid receptor. It is prepared from salvinorin B. The crystal structure is almost superimposable with that of salvinorin A. Structures bound to the ú-opioid receptor have also been reported.
Salvinorin B methoxymethyl ether has a K<sub>i</sub> of 0.60 nM at the ú opioid receptor, and is around five times more potent than salvinorin A in animal studies, although it is still only half as potent as its ethoxymethyl ether homologue, salvinorin B ethoxymethyl ether (2-O-ethoxymethylsalvinorin B; 2-EMSB; "symmetry").
The drug was encountered online as a novel designer drug in 2020.