Endor studies of cation radicals from pharmacologically active phenothiazines

A variety of substituted phenothiazine cation radicals, including those from pharmacologically active derivatives, e.g. chlorpromazine, alimemazine and laevomepromazine, have been studied by means of ENDOR and TRIPLE resonance spectroscopy. These techniques allowed accurate determinations of hyperfine coupling constants, including their signs. Conclusions concerning molecular structure (e.g. twist angles) could be drawn, supporting previous investigations of the interrelationship of molecular conformations with the pharmacological potential, i.e. neuroleptic, antihistaminic or anti‐Parkinsonian.