Enloplatin can be obtained by two related ways: 1) The cyclization of 2,2'-dichloroethylether (I) with malonodinitrile (II) by means of K2CO3 in refluxing acetonitrile gives tetrahydropyran-4,4-dicarbonitrile (III), which is reduced with BH3 in THF yielding tetrahydropyran-4,4-dimethamine (IV). The reaction of (IV) with potassium tetrachloroplatinate (V) affords dichloro(tetrahydropyran-4,4-dimethanamine-N,N')platinum(II) (VI), which is finally condensed with cyclobutane-1,1-dicarboxylic acid silver salt (VIII) in water. 2) The reaction of potassium tetrachloroplatinate (V) with DMSO gives dichloro-bis(dimethylsulfoxide)platinum(II) (VII), which is condensed with silver salt (VIII) to afford (1,1-cyclobutane-dicarboxylato-O,O')bis(dimethylsulfoxide)platinum(II) (IX), which is finally treated with diamine (IV) as before.
Zeniplatin can be obtained by two related ways: 1) The reaction of dimethylsulfoxide with potassium tetrachloroplatinate (I) gives bis(dimethylsulfoxide-S,S')dichloroplatinum (II), which is then condensed with silver cyclobutane-1,1-dicarboxylate (III) in water to yield bis(dimethylsulfoxide-S,S')(1,1-cyclobutanedicarboxylato-O,O')platinum (IV). Finally, this compound is treated with 2,2-bis(aminomethyl)-1,3-propanediol (V) in refluxing water. 2) The reaction of potassium tetrachloroplatinate (I) with diamine (V) in water gives [2,2-bis(aminomethyl)-1,3-propanediol-N,N']dichloroplatinum (IV), which is treated with the silver salt (III) as before. The diamine (V) is prepared by reaction of 2,2-bis(bromomethyl)-1,3-propanediol (VII) with sodium azide in hot DMF to give 2,2-bis(azidomethyl)-1,3-propanediol (VIII), which is then reduced with hydrogen over Pt.