REACTION OF 4-PICOLINE(2,2' 6', 2''-TERPYRIDINE)PLATINUM(II) WITH NUCLEOSIDES/

The four nucleosides found in DNA react with 4-picoline(2,2' -6',2 ''- terpyridine)platinum(II). Guanosine and 2'-deoxyguanosine are platinat ed at N-7. Adenosine and 2'-deoxyadenosine are platinated at both N-1 and N-6 With loss of a proton and there is no evidence of monoplatinat ed intermediates. It is proposed that platination occurs initially at N-1, the most nucleophilic site, which leads to loss of a proton from the N-6 amino function and subsequent rapid platination at this site. This conclusion is supported by NMR and mass spectral evidence. 2'-Deo xycytidine is similarly platinated at N-3 and N-4 and a similar explan ation is proposed. Platination of thymidine is very slow and the produ ct(s) has not been characterised.