What if the amino acid, Phenylalanine was methylated at the alpha position ......
            CH3  O
                 |   ||
C6H5-CH2-C-C-OH
                 |
                 NH2


then decarboxylated?  It would leave the Amphetamine.

So, is there a method to methylate the alpha carbon without polymerizing the amine? Actually if the amine got methylated it would be even better........java

This has been covered to great lenghts in the past...