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Novel ephedrine reduction idea

Started by Rhodium, August 09, 2002, 11:34:00 AM

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Rhodium

Ephedrine (or pseudoephedrine) is reacted with an excess of p-toluenesulfonyl chloride to form O,N-ditosyl-ephedrine, which is reacted with an excess of lithium powder in the presence of a catalytic amount of naphtalene in THF at dry ice temperature, which exchanges the O-tosyl leaving group for a lithium ion, giving 1-lithio-N-tosylephedrine, which upon quenching with a proton donor (ammonium chloride, alcohol etc) should give N-tosyl-methamphetamine.

See

https://www.thevespiary.org/rhodium/Rhodium/pdf/alkylsulfate2alkyllithium.pdf

for the R1O-SO2-OR2 -> R1Li + R2Li reaction.

Reflux of N-tosyl-methamphetamine with a phenol in Hydrobromic acid for 20 minutes deprotects the nitrogen, giving d-Methamphetamine in 90% yield from the sulfonamide, see

Post 339848

(Rhodium: "Sulfonamide cleavage", Novel Discourse)
.