Nevermind, found it. I guess you can delete these last two post since they aren't related to the topic. Here's the synthesis if you was interested.
Retrieve from a Hive Achieve. A Bee that goes by Bandil wrote it up on 09-08-02 08:03.
28,2(150 mmol) g (-/+)-norephedrine was dissolved in 141 mL's tap water at rt. in a 500 mL FB. erlenmeyer flask.
The whole lot dissolved without any problems. Next 12,0 g of KOCN was dumped into this soln. No heat evolution was noted. With some stirring with a mag bar, 75% of the KOCN dissovled.
The bottle was rigged for reflux and submerged in an oilbath at about 140 deg. cel. After the temp. of the liquid in the bottle reached 35 deg. everything had dissolved and it looked like plain water. Soon the whole thing began to reflux nicely. The smell reminded a bit of old wet clothes, but swim is not sure that it was the reaction that caused this.
After 2½ hour the apperance of the liquid had not changed. The erlenmeyer flask was removed from the oil bath and allowed to cool at RT. When the flask reached 70 deg, swim believed it was ok to cool it with running water. Almost immediately when the cold water touched the surface of the flask, a clear oil precipitated on top of the water. With further cooling, more appeared. Soon white flakes started to appear at the bottom. The flask was placed in the freezer for ½ an hour, till the temp. inside the liquid has droppet to 5 deg. cel. At this point the flask was white with something that did not resemble PPA nor KOCN . The product was allowed to dry somewhat, but swim did not have enough time to let it dry completely, so he estimated there where 18 grammes(according to the original patent)(86,6 mmol). It should be noticed here that swim probably SHOULD have compensated for the missing CH2 group in the PPA to eph with 6% wt, but he did not bother as the last reaction uses only hydrochloric acid.
The wet carbamyl was put into 275 mL of water in a 500 mL FB flask and dissolved only lightly. Next 172 mL of 2M hydrochloric acid was added. No reaction could be noted. A stirr bar was put in and the whole lot was refluxed for about 2,5 hours. When the temp of the water reached about 50-60 deg celc, everything had dissolved and the liquid seemed like water again.
After 2,5 hours, swim removed the bottle and let it cool to RT. a soln of 20% Na2CO3 was added, while stirring, til no more white powder appeared. Swim was of course VERY thrilled when the white stuff precipated as an amide would not have done whis and PPA would be oily on freebase, so something had happened . The white precipitate was gravitity filtered and some of it was dried. Swim does not have an exact yeild, but will post it later, when the whole mass has dried. It sure did look like ALOT
Topic: Phenylpropanolamine to Ephedrine (Read 487 times)
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Are there any easier reductions, preferably referenced? That method also produces a mixture of mono-, di- and tri-methylated amines and starting material so it could be quite dirty. They don't say much about the make up of the finished reaction mixture. Unless a far friendlier reduction works for this, I don't think methylating the amine prior to reducing the the hydroxyl is the best route if desoxyephedrine is your hypothetical target.
