Regiospecific Functionalization of Pharmaceuticals and Other Biologically Active Molecules through Cyclopalladated Compounds. 2-Iodination of Phentermine and L-Tryptophan Methyl Ester

摘要: Phentermine hydrochloride ((PhCH2CMe2NH3)Cl) or l-tryptophan methyl ester ([C8H6NCH2CH(CO2Me)NH3]Cl) reacts with Pd(OAc)2 in a 1:1 molar ratio to give the cyclometalated complex [Pd2(κ2-C,N-C6H4CH2CMe2NH2-2)2(μ-Cl)2] (1) (S,S)-[Pd2{κ2-C,N-C8H5NCH2CH(CO2Me)NH2-2}2(μ-Cl)2] (2), respectively. Reaction of 1 2 iodine affords trans-[PdCl2(NH2CMe2CH2C6H4I-2)2] (3) trans-(S,S)-[PdCl2{NH2CH(CO2Me)CH2C8H5NI-2}2] (4), which further 1,10-phenanthroline [PdCl2(phen)] and free amine 2-I-phentermine (5) (S)-2-I-tryptophan (6) (overall yields 44 51%, respectively, considering phentermine as starting materials). The crystal structure 3 has been determined by X-ray diffraction studies.