In previous papers of this series we have reported that AT-584 (Ⅰ) had tumour-inhibiting property with long-acting efficacy in experimental animals.It seemed, there-fore, desirable to modify this structure in order to see whether the antitumour property was due to the quarternary structure or the mustard group. In the present investigation the structure of AT-584 was varied in five ways:(1)the replacement of bromide ion by chloride and iodide (Ⅱ);(2) the replacement of hexamethylenetetramine by other organic bases, such as pyridine, N-methyl-piperidine, and thiourea (Ⅲ);(3) the replacement of the quarternary ammonium moiety with tertiary bases (Ⅳ);(4) the replacement of the mustard group by various electro-negative and electro-positive groups (Ⅵ);(5) since AT-584 might undergo the Delepine reaction as one of its metabolic route,p-bis (2一chloroethyl)-amino-uraminoacetophenone hydrochloride (Ⅴ, AT-805) was synthesized.