Platinum(II) complex and antitumor agent

A platinum(II) complex represented by the general formula:

• ##STR19## in which R.sub.1 represents an aliphatic hydrocarbon radical having 1 to 10 carbon atoms, R.sub.2 and R.sub.3 each represent a hydrogen atom or an aliphatic hydrocarbon radical having 1 to 10 carbon atoms, or R.sub.2 and R.sub.3, together, form --(CH.sub.2).sub.4 -- or (CH.sub.2).sub.5 --, R.sub.4 and R.sub.5 each represent a hydrogen atom or an aliphatic hydrocarbon radical or aliphatic hydrocarbon ether radical having 1 to 6 carbon atoms, the carbon atoms of the moiety ##STR20## being not more than 10, or R.sub.4 and R.sub.5, together, form --(CH.sub.2).sub.l --, in which l is an integer of 3 to 5, or --(CH.sub.2 ).sub.2 --O--(CH.sub.2).sub.2 --, and m is 1 or 2.

An agent for treating tumor comprising an anti-tumor effective amount of platinum(II) complex represented by the general formula:

• ##STR21## in which R.sub.1 represents an aliphatic hydrocarbon radical having 1 to 10 carbon atoms, R.sub.2 and R.sub.3 each represent a hydrogen atom or an aliphatic hydrocarbon radical having 1 to 10 carbon atoms, or R.sub.2 and R.sub.3, together, form --(CH.sub.2).sub.4 -- or --(CH.sub.2).sub.5 --, R.sub.4 and R.sub.5 each represent a hydrogen atom or an aliphatic hydrocarbon radical or aliphatic hydrocarbon ether radical having 1 to 6 carbon atoms, the carbon atoms or the moiety ##STR22## being not more than 10, or R.sub.4 and R.sub.5, together, form --(CH.sub.2).sub.l --, in which l is an integer of 3 to 5, or --(CH.sub.2 ).sub.2 --O--(CH.sub.2).sub.2 --, and m is 1 or 2 is a pharmaceutically acceptable vehicle.