Oligopeptide-like derivatives structurally related to the antitumor agent tallimustine, where one or two pyrrole rings were replaced by pyrazole or thiazole rings and bearing benzoyl nitrogen mustard or bromoacryloyl moieties were synthesized and evaluated in vitro and in vivo against L1210 murine leukemia. Compounds 9 and 12 showed antitumor activity higher than or comparable with that of tallimustine. Copyright (C) 1996 Elsevier Science Ltd