The invention relates to the compounds of formula: ##STR1##

as well as to the salts thereof with inorganic or organic acids, to solvates thereof and/or to hydrates thereof, which have strong affinity and high selectivity for the human NK₁ receptors of substance P. The invention also relates to the process for preparing them, to the intermediate compounds of formula (VII) which are useful for the preparation, to pharmaceutical compositions containing them and to their fuse for the manufacture of medicinal products intended for treating any pathology in which substance P and the human NK₁ receptors are involved.