JV-Methyltyramine

The most abundant alkaloid in Coryphantha macromeris, normacromerine, has been shown to originate from tyrosine (330). Tyramine and JV-methyltyramine are efficiently incorporated into normacromerine while octopamine and dopamine are poor precursors. Norepinephrine, epinephrine, normetanephrine, and meta-nephrine have all been shown to be biosynthetically incorporated into normacromerine, and they have also been shown to be naturally occurring trace intermediates in this cactus species (331, 334). Normacromerine is only slowly converted to macromerine in C. macromeris (332). The results indicate that alternative pathways to normacromerine exist precise conclusions regarding the biosynthesis of normacromerine must await further studies. 

As part of an extensive chemical investigation of the Croton genus (see Section 3D), Croton humilis has been examined and shown to contain jV-methyltyramine... 

There is little doubt that other 8-phenethylamines will be found to be primary plant constituents and their structures can even be predicted based on the regularity with which the substituents appear to occur in the already known natural compounds. A missing link has been recently discovered by Kirkwood and Marion (4) in certain strains of barley. The newly found JV-methyltyramine completes the series which begins with tyramine and terminates in the quaternaiy cactus alkaloid candicine. 

Corti (48) prepared the base by heating JV-methyltyrosine, suspended in fluorene, at 250°. Kirkwood and Marion (4) condensed 0-methyl-tyramine with benzaldehyde and treated the derived benzal derivative with dimethyl sulfate. After decomposition of the quaternary compound and hydrolysis of the O-methyl-A-methyltyramine with hydro-bromic acid JV-methyltyramine was obtained. 

JV-Chloroacetyl-p-O-methyltyramine (351) behaves in a different fashion and, on irradiation, is converted into the bicyclic rearrangement product (352).382,383 The suggestion has been made that this rearrangement is the result of homolytic carbon-chlorine bond cleavage, followed by radical attack on the aromatic system, and the proposed sequence of events is outlined in Eq. (98). 

The following bases were isolated as their hydrochlorides JV-methyl-4-methoxy-jS-phenethylamine, hordenine, iV-methyltyramine, syne-phrine, and O-methylsynephrine (38). 

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