Cytosine Dilute solutions

The product from Step 5 (Immol) and cytosine (Immol) were dissolved in acetonitrile (25mmol), hexamethyldisilazane (Immol) and chlorotrimethylsilane (4mmol) added, and the mixture stirred at ambient temperature 30 minutes. The solution was cooled to -78 °C, trimethylsilyltrifluoromethane sulfonate (1.2 mmol) added, and the solution stirred 2.5 hours. Thereafter, the mixture was warmed to ambient temperature, concentrated to 5 ml, diluted with 50 ml CH2CI2, washed with 20 ml water, dried, and concentrated. The residue was purified by chromatography over silica gel using chloroform/methyl alcohol, 98 2, and the product isolated in 77.5% yield. H-NMR, elemental analysis, and MS data supplied. 

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