Synthesis and characterization of compounds of di- and tributyltin chloride with adenine and guanine mononucleotides

Compounds have been synthesized between Bu2SnCl2 or Bu3SnCl (Bu = n-C4Hv) a nd the nucleoside monophosphates adenosine 5'-monophosphate (5'-AMP), and g uanosine 5'-monophosphate (5'-GMP), and their 3'-5' cyclic analogs. The sto ichiometry of the compounds of 5'-AMP and 5'-GMP with Bu3SnCl was 1:2 while that with Bu2SnCl2 was 1:1. Only 1:1 compounds were obtained with the 3'-5 ' cyclic nucleotides. The compounds were characterized by H-1 C-13, and P-3 1 NMR in DMSO and solid state IR spectroscopy, and to some extent, mass spe ctrometry. (Bu3Sn)(2)(5'-AMP) and (Bu3Sn)(2)(5'-GMP) appear to be monomeric with one Bu3Sn moiety bonded to the phosphate and the other one bonded to the 3'-oxygen of the ribose. However, a dimeric or small polymeric structur e is possible. Bu2Sn(5'-AMP) and Bu2Sn(S'-GMP) are polymeric and differ in that in the latter compound the two butyl groups are in different environme nts while in the former compound both butyl groups an the same. For all of the Bu3Sn compounds, P-31 NMR chemical shifts indicate that tin is bonded t o the phosphate group, but probably not chelated by it. A much larger P-31 upfield shift in (Bu3Sn)(2)(5'-GMP) is an indication of phosphate chelation . Structures are proposed for some of the compounds. The ribose conformatio n in the Bu3Sn nucleotides is C2'-endo and C3'-endo in the Bu2Sn nucleotide s. (C) 1999 Elsevier Science S.A. All rights reserved.