I've started a new threat because the old one was getting rather long and confusing. I'm still sure that it's norephedrine and not norpseudoephedrine that is required for this synthesis. Allow me to proof my point:
(taken from J.Chem.Soc. 1,(1952),p. 850 and 851) :
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"We now find that, whether alkaline hydrolysis of N-cyano-(+-)-ephedrine leads to (+-)-ephedrine, hydrolysis with dilute acid gives, in high yield, 2-imino-3,4-dimethyl-5-phenyloxazolidine; the configuration of it being proved by its alkaline hydrolysis yielding exclusively pseudoephedrine."
[...]
"In order to decide between these two alternatives, N-carbamyl-(+-)-ephedrine prepared from (+-)-ephedrine.HCl, was also treated with dilute acid, 2-imino-3,4-dimethyl-5-phenyloxazolidine was again obtained. It seems therefore reasonable to assume that inversion of the configuration was induced by a nucleophilic attack by the ureido-oxygen atom, trans -placed with respect to the hydroxyl group."
[...]
"By treatment of (+-)-pseudoephedrine with KOCN the urea was obtained. However, in conditions identical with those used for the conversion of N-carbamyl-(+-)-ephedrine into 2-imino-3,4-dimethyl-5-phenyloxazolidine ; N-carbamyl-(+-)-pseudoephedrine gave (+-)-3,4-dimethyl-5-phenyloxazolid-2-one by loss of ammonia.
The oxazolidone must have been formed directly from N-carbamyl-(+-)-pseudoephedrine and not via N-carbamyl-(+-)-ephedrine, as the latter was not affected by similar treatment. The configuration of it is proved by its preparation from (+-)-pseudoephedrine and carbonyl chloride and from 2-imino-3,4-dimethyl-5-phenyloxazolidine and nitrous acid."
[...]
"In N-carbamyl-(+-)-ephedrine the hydroxyl and the ureido-group must accordingly be trans -placed."
[...]
"The reaction of pseudoephedrine with CNBr under anhydrous conditions gave 2-imino-3,4-dimethyl-5-phenyloxazolidine ; already obtained from N-cyano-(+-)-ephedrine and from (+-)-ephedrine *via* N-carbamyl-(+-)-ephedrine. "
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We know already that heating PPA.HCl with 25% HCl, or hydrolysis of chloro-PPA.HCl (sat'd HCl at 0œC) gives a 50/50 mixture of norephedrine and norpseudoephedrine, and I have promised you all that I have a ref on the separation of these two via their bitartrate salts, well, here it is:
taken from Helv.Chim.Acta 22,(1939),p.365
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15grs of the mixture of the bases are dissolved in 40 ml warm water with 15 grs of tartaric acid. After a short time norpseudoephedrine bitartrate precipitates (mp 202œC).
Filter this off and evaporate the water. Recrystallise the residue with alcohol: norephedrine bitartrate (mp 130-160œC)
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l-norephedrine base: mp 50œC
norephedrine.HCl : mp 171-172œC
norephedrine.HSO4 : mp 285-286œC
d-norpseudoephedrine.HSO4 : mp 290-291œC
I hope this will clarifie this issue somewhat, we are looking here on an OTC, non-toxic and high-yielding synthesis of 4-MAR; aren't there any people around here who could confirm this all by actually trying it out? SWIM has some chloro-PPA.HCl sitting in the freezer but he is really busy at the moment and there not much time for chemistry
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