Tris guanine, preparation

Tris(trimethylsilyl)guanine was prepared from guanine using 3 molar cquiv of TMSCl and EijN for 4 d at 40 C, From guanine (10 g, 66.2 mmol), 18.2 g of the product (74%) was obtained, bp 167- 168 "C/1 Torr 1.9 g of guanine was recovered. All trimcthylsilyl derivatives of the purines described decompose readily in aq EtOH. 

Several square planar Pt complexes with bases, nucleosides, and nucleotides have been characterized. A series of guanine-derived complexes have been prepared with both cis- and trani-geometries. These complexes generally show Pt coordination to the N7 position except when that position is blocked and coordination to the N1 position can be observed. In the case of adenine, Pt coordination to both N7 and N1 is feasible. The crystal structure of bis-adenine Pt bound to the N7 position with irans-geometry has been reported. The mono-, bis-, and tris-cytosine Pt complexes all exhibit coordination to the N3 position. " " A number of mixed-base compounds have been prepared. ... 

Standard condensation procedures have been used to prepare 7- and 9-(6 -deoxy-a-L-talofuranos l) derivatives of hypoxanthine, guanine, and 6-thio-purine, the derivatives of the last purine shov/ing marked antitumour activity. 2-Deoxy-D-ribofuranosyl chloride condensed with N-trimethylsilyl-4-carboxymethyl-5-cyanomethylimidazole in presence of stannic chloride (best catalyst tried) gave a- and... 

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