Cathinone synthesis

Ecstasy synthesis patterned on cathinone from Catha edulis Forsk., Celestraceae, Ang. 

A stereospecific synthesis of (S)-(—)-cathinone that utilizes the Friedel-Crafts reaction has been described (3/7). Reaction of the acid chloride obtained from /V-(methoxycarbonyl)-L-alanine (10) in benzene by A1C13 catalysis provided the N-protected a-amino ketone 11 with retention of chiralty 11 was deprotected by hydrolysis with potassium hydroxide. A more recently published method (408)... 

Merucathinone was synthesized by Wolf and Pfander (79) from rerr-butoxycar-bonyl-L-alanine (Scheme 4). Treatment with n-butyllithium and styryllithium as before formed 20, which was deblocked with trifluoroacetic acid to give merucathinone (6), isolated as the oxalate. As assessed by treatment with (+)-l-phenylethyl isocyanate and HPLC, the optical purity of 6 was greater than 97%. Treatment of r-BOC-L-alanine with 3 equiv of phenyllithium gave ketone 21, which was deblocked as before to provide a short synthesis of cathinone (2), isolated as its hydrochloride (enantiomeric excess >95%) (19). 

The total synthesis of optically active cathinone was achieved using race-mized norephedrine as the starting material [9]. On the other hand, the total syntheses of merucathinone and merucathine were accomplished using L-alanine as the starting material. Initially, the absolute stereochemistry of merucathine was elucidated to be (35,45) [8], but this was correaed to (3R,4R) after the completion of its total synthesis [10]. 

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