Antitumor platinum(II) complexes of N-monoalkyl-1R, 2R-diaminocyclohexane derivatives with alkyl groups as hindrance.

A number of platinum (II) complexes, characteristic of (1R,2R)-N(1)-alkyl-1,2-diaminocyclohexane derivatives as carrier ligands, were designed, synthesized and characterized, where the alkyl group serving as hindrance is a 1-butyl, 2-methylpropyl or 2-butyl moiety, respectively. In vitro biological evaluation of these platinum complexes revealed that their antitumor activity had a close relationship with the shape of alkyl groups. In vivo antitumor study indicated that complex 1c, [(1R,2R)-N(1)-(2-butyl)-1,2-cyclohexanediamine-N,N'] (oxalato-O,O')platinum (II), possessed rather high antitumor effect and low toxicity compared with cisplatin and oxaliplatin. Antitumor mechanism of 1c has been tentatively studied, which might be different from that of cisplatin and oxaliplatin.