Effective complexation of psychotropic phenethylammonium salts from a disodium dipyrazolate salt of macrocyclic structure

Abstract

The equilibrium stability constants (K_s) of ammonium pyrazolate complexes [L²⁻]2RN(R′)H₂⁺ (3, R′ = H and 4, R′ = Me) formed from a macrocyclic disodium dipyrazolate salt 2[L²⁻] 2Na⁺ and ammonium salts (RNH₃⁺X⁻ or RN(Me)H₂⁺X⁻) of psychotropic drugs and neurotransmitter catecholamines have been evaluated by electrochemical methods in DMSO solution. The resulting K_s values demonstrate that, except for (±)-amphetamine, the complexes formed by lipophilic primary [mescaline, (+)-amphetamine, (±)-p-methoxyamphetamine (PMA), (±)-3,4-methylenedioxyamphetamine (MDA)] and secondary [(±)-methamphetamine, (+)-methamphetamine and (±)-3,4-methylenedioxymethamphetamine (MDMA ‘ecstasy’)] phenethylamines are more stable than those formed from hydrophilic ones (dopamine and norepinephrine). A ¹H and ¹³C NMR study on the formation of complexes of structure 3 and 4 formed from primary [mescaline, (+)-amphetamine] and secondary [(+)-methamphetamine] ammonium salts is given.