Hydrochloric Acid → HSeCH(COOC2H5)2

15 mmol of ClCH(COOC2H5)2 and 10 mmol of sodium selenide were heated in 50 ml of ethanol under reflux for 2 hours. After completion of the reaction, the reaction solution was slightly acidified with 1N HCl. Then, after insoluble material was removed from the solution, the reaction solvent was distilled off to obtain HSeCH(COOC2H5)2. The thus obtained HSeCH(COOC2H5)2 was put in aqueous ammonia and the reaction was allowed to proceed at 50° C. for 6 hours. After completion of the reaction, the solvent was distilled off to obtain HSeCH(CONH2)2. To the thus obtained HSeCH(CONH2)2 were added 50 ml of tetrahydrofuran and then 2 mmol of lithium aluminum hydride. The resulting mixture was heated under reflux for 10 hours to reduce the amide. After completion of the reaction, the insoluble portion was removed and the solvent was distilled off under reduced pressure. Then, the residue was purified by using cation exchange resin to obtain 2 mmol of 2-seleno-1,3-diaminopropane HSeCH(CH2NH2)2. To the thus obtained HSeCH(CH2NH2)2 was added 20 ml of an aqueous solution containing 2 mmol of potassium tetrachloroplatinate(II) and the resulting mixture was allowed to stand at room temperature for 4 days, so that a precipitate was formed. The precipitate was separated by filtration and dried to obtain 1.1 mmol of HSeCH(CH2NH2)2PtCl2.