Improved process for preparing methadone precursor

[pHarmacist]

Patent US4242274

BACKGROUND OF THE INVENTION:
 
This invention relates to the manufacture of methadone and more particularly to an improved process for preparing the methadone precursor 2,2-diphenyl-4-(dimethylamino)-pentane nitrile.

...

Abstract

A process for the preparation of 2,2-diphenyl-4-(dimethylamino)-pentane nitrile. A charge mixture is prepared comprising diphenylacetonitrile, 1-(dimethylamino)-2-halopropane, a base, water, a water-immiscible organic solvent, and a quaternary salt selected from a group consisting of tetrabutylammonium halides, tetrabutylammonium hydrogen sulfate, cetyltrimethylammonium halides, benzyltriphenylphosphonium halides, and methyltrialkyl (C.sub.8 -C.sub.10) ammonium halides. The mixture is heated under an inert atmosphere to effect formation of 2,2-diphenyl-4-(dimethylamino)-pentane nitrile by reaction of diphenylacetonitrile, 1-(dimethylamino)-2-halopropane and a base.

1-2-3 ACiD

[Cyrax]

This is a very nice patent.  In my book, Mallinckrodt inc is an authority when it comes to cooking up analgesics.  And wow, they even give yields (most patents don't ...).

Thanks for bringing this to my attention.  Keep up the good work, pHarmacist.