and 10b). Derivatives 4a,b, 6a,b–10a,b were tested for in vitro alkylating activity while compounds 7a, 7b and 9a were tested for in vivo antitumor activity. As determined by in vitro Preussmann tests, compounds 4, 6 and 7 possess strong alkylating activity. Compounds 10 have moderate potential for alkylation, whereas the remaining compounds 8 and 9 are only weakly active. The derivatives 7a, 7b and