As shown in Scheme 5, compounds of Formulae (Ib) and (Ic) can be prepared by reacting a carboxylic acid 32 (obtained from treatment of carbidopa with (Boc)2O in methanol) with an appropriate halide 33 or a compound of Formula 35, wherein D is OH, NH2, NHR15, halide or other leaving group, under appropriate alkylation or coupling conditions to provide compounds of Formulae 36 and 38, respectively.