Fencamfamin configuration?

[absinthoman]

Hi,

I am a new member of this forum but I have been reading for while... I am really interested in the fencamfamin. Unfortunately I can't find the absolute configuration of the molecule? Anybody could direct me to a link where I could access this information? Thank you guys.

 

[sekio]

The (2-endo, 3-exo - 1a) is 90% prevalence with the (2-exo, 3-endo - 1b) taking the other 10%. Fencamfamine's route of synthesis involves a Diels-Alder reaction so unless you start messing with chiral catalysts it should come as a racemic salt. No idea on which isomer is most active.

(M. Thunhorst et al. / J. Chromatogr. A 818 (1998.) 239 –249)

Presumably this holds true to camfetamine, the N-methyl analog.

 

[absinthoman]

So as I understand, they use a mixture of 90 % 1a and 10 % 1b.

I know we can't talk synthesis here so let's not talk about the synthesis of these materials...

I am just curious about the enantio-purity. 1a and 1b are diastereoisomers but do they use the racemic of each in the formulation or they use the enantiomers shown on the fig. (1a and 1b) only.

I know 1a and 1b could probably be separated by a MPLC (medium pressure chromatography) aka combiflash and maybe or maybe a normal silica chromatography but their enantiomers could'nt be separated.

 

[sekio]

It's a racemate as far as I know.

Technically there are 4 molecules that can be called fencamfamine.
(+)-(endo,exo)-fc
(-)-(endo,exo)-fc
(+)-(exo,endo)-fc
(-)-(exo,endo)-fc

The +/- enantiomers would seperate if you had e.g. chiral GC columns. the endo/exo isomers seperate on normal GC or HPLC. As far as I know, fencamfamine is not used as an optically active salt.