1 -Methylcytosine, platinum complex

Ruiz J, Cutillas N, Vicente C, Villa MD, Lopez G, Lorenzo J, Aviles FX, Moreno V, Bautista D (2005) New palladium(II) and platinum(II) complexes with the model nucleobase 1-methylcytosine antitumor activity and interactions with DNA. Inorg Chem 44 ... 

Somewhat more loosely related to platinum antitumor drugs were EHMO calculations performed on heterobimetallic Pt-Pd complexes with a bridging methylcytosinate anion by Mealli, Randaccio, Lippert, and coworkers [31][32], The calculations served to elucidate the metal-metal and metal-ligand binding interactions, and yielded a qualitative interpretation of the 195Pt-NMR chemical shifts. 

It has been demonstrated that the tran5 -[(NH3)2PtCl] adduct of 1-methylcytosine, bound via N-3, can form crosslinks with either 9-ethylguanine or 9-methyladenine as a result of Cl substitution by purine N-7 atoms. Additional H-bonds between exocyclic groups of cross-linked nucleic acid bases provide additional stabihzation of the individual complexes (Figure 13d). Binding of the related complex [(NH3)2Pt(N-3-cytosine)Cl]+ with d(GG) leads to the formation of a major product in which the platinum is bound only to N-7 of the 5 -nucleotide. ... 

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