Forming Imine Before Hand?

[CryoThio]

I was just thinking about how the imine is formed before adding sodium borohydride, and I was wondering if this was applicable to amalgam reactions.

Would this even make a difference? Say forming the imine and pouring/dripping that solution into a reaction vessel with a mercury amalgam? Would it even work this way?

I'm wondering if doing this is possible, and if it changes anything (it would be nice that could allow for "denser" reactions, having more ketone/iminein the reaction vessel than a "normal" amalgam.

 

[OrgUnikum]

Nope. The solvent volume is determined by the aluminium needed for the reduction. An old French patent claims this anmount could be very much reduced by running this under pressure and using di-ethyl ether or THF as solvent. I guess thats right.
I knew people who ran the "Methylman" (Nitromethane instead of Methylamine) which is much worse regarding needed volume and Al in a modified pressure cooker reducing the needed Al (and volume) by half. They had no problems but this is quite daring taking into account that the reaction is VERY lively to start with.

The Imine of MDP2P or P2P are both not stable but they hydrolyze in the presence of water back to the strating compounds and reform again. Thats why the Ketone is dripped slowly into a big excess of Amine to keep the equilibrium on the Imine side and have this reduced as the side-reaction is reduction of the Ketone to the Alcohol.
MDM-Imine is much more stable then Methamphet-Imine and therefor a much higher excess of Methylamine is needed to get decent yields for Meth then for MDMA. No biggie as the excess MeNH2 can be easily recovered and re-used.