Alkylating nucleosides. 3 . The reaction of 3,5‐dimethylpyrazole nucleosides with N ‐bromosuccinimide

Bromination of 3,5‐dimethylpyrazole nucleosides with N ‐bromosuccinimide gave the corresponding 4‐bromo‐3,5‐dimethylpyrazole, 3‐methyl‐5‐(bromomethyl)pyrazole and 4‐bromo‐3‐methyl‐5‐(bromomethyl)pyrazole nucleosides. Structural assignments were made on basis of analytical and 1 H nmr spectral data. All of the bromomethylpyrazole nucleosides described showed cytostatic activity against HeLa cell sultures.