From: Anonymous <Use-Author-Address-Header@[127.1]>
Date: Tue, 23 Dec 1997 16:24:29 -0500
Newsgroups: rec.drugs.chemistry,alt.drugs.chemistry
Subject: Re: Birch reduction procedure

On Fri, 19 Dec 1997 07:42:26 -0600 "T Jo" <tjo331@airmail.net>  wrote:

>Can anyone outline the procedure for the reduction of ephedrine using
>ammonia & lithium metal?
>
> HERE IT IS: MAYBE SOMEONE CAN PUT A COPY IN the Hyperreal & Lycaeum archives??

From Ely & McGarth J Forensic Sci 35:720-3, 1990 verbatim

Procedure

        All chemicals were reagent grade, with no special treatment of the
tetrahydrofuran (THF), and the atmosphere above the condensed ammonia was
not flushed with nitrogen gas. 
        A three-neck flask was cooled in a dry ice/acetone bath. A
condenser was fitted in the center neck, an additional funnel containing
l-ephedrine base in THF was fitted into one side neck, and a rubber
stopper fitted with a glass tube extending to the bottom of the flask was
fitted in the third neck. Anhydrous ammonia gas was condensed and
collected in the flask. Small pieces of lithium metal were rinsed in
petroleum ether, patted dry, and added to the condensed ammonia. A deep
royal blue color was noted as the lithium metal dissolved in the condensed
ammonia. 
        The l-ephedrine was added dropwise to the lithium ammonia solution
over a period of approximately 10 min. with stirring. When all of the
l-ephedrine had been added, ammonium chloride was added slowly to the
solution. The flask was removed from the cooling bath, and the cooled
ammonia was allowed to warm to room temperature and evaporate from the
flask through the side necks. 
        When most of the ammonia had evaporated, water was added to the
remaining solution until it cleared and any remaining lithium metal was
decomposed. The remaining solution was removed from the flask to a
separatory funnel, where the aqueous layer was discarded. The THF layer
was dried with magnesium sulfate, and the hydrochloride salt of the
methamphetamine was made by bubbling hydrogen chloride through the THF. 
        ......  
        The time required for the reaction to proceed from the
condensing of the ammonia gas in the reaction flask until the excess
lithium was decomposed was approximately 1 h. The majority of the time was
spent waiting for the condensed ammonia to evaporate from the reaction
flask. 
        The reaction was found to reduce l-ephedrine to d-methamphetamine
quickly and easily. Furthermore, it was found that the reaction converted
phenylpropanolamine to amphetamine and methylephedrine to
dimethylamphetamine. It was also found [in a second synthesis] that the
ephedrine would reduce to methamphetamine without the addition of ammonium
chloride as a quenching agent. 

[Note: reformatted to eliminate >80 character lines -- lamont]
