Nucleic acid related compounds. 38. Smooth and high-yield iodination and chlorination at C-5 of uracil bases and <i>p</i>-toluyl-protected nucleosides

Abstract

Treatment of uracil bases and protected nucleosides with iodine monochloride (ICl) gave the corresponding 5-iodouracil products in over 95% purified yields. Analogously facile chlorination was effected with iodobenzene dichloride (PhICl 2 ). Protection of the nucleosides as p-toluyl esters provided reactants that were soluble in organic solvents and crystallized readily in high yields.