Reduction Reinecke salt

Occasionally isolation of a particular alkaloid is facilitated by forming a water insoluble salt, nitric, perchloric, sulphuric and oxalic acids have often been used for this purpose but this does not form part of any systematic procedure except for the removal of water soluble bases from aqueous solution. Thus for quaternary salts picric acid and reinecke salts have been widely used. N-oxides also form water insoluble derivatives with many acids but this problem can usually be dealt with by reduction back to the parent tertiary base which is then soluble in organic solvents. 

The reactions described so far all yield medium-ring tertiary amines. Reinecke s group have recently extended their methods to synthesize the more useful secondary amines.288 Three syntheses were developed. The first [Eq. (31)] involves reductive cleavage of the benzyl indolizidinium salt 229 with lithium aluminum hydride, followed by replacement of the benzyl group with the labile trichloroethoxycarbonyl group. The latter may be removed under mild conditions with zinc-methanol, which does not cause migration of the double bond. 

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