HYDROGEN-BONDING STABILIZATION OF N-METHYLDOPAMINE 4-O-DIHYDROGENPHOSPHATE IN HCL ACIDIC SOLUTION - SYNTHESIS OF Z2055, A NEW DOPAMINERGIC PRODRUG

The crystal structure analysis of 4-[2-(methylamino)ethyl]-1,2-benzene diol 1-(dihydrogenphospate) hydrochloride, C9H15NO5P+. C1(-), shows th at the Cl- ion is an acceptor in a hydrogen-bonding system joining the ammonium cations in endless chains and involving one phosphate and th e phenol hydroxyl groups together with the ammonium group, acting as p roton donors. The stability of this system may justify the isomerizati on of the 4-hydroxy-3-O-phosphate to 3-hydroxy-4-O-phosphatephenethyl moiety, observed in strongly acidic HCl solution. This isomerization a llows simplification of the synthesis of the Z2055 dopaminergic prodru g.