Mercaptomethylpyrazolopyrimidine (2) was synthesized and reacted with ethyl
chloroacetate to afford ethyl pyrazolpyrimidinylmethylmercapto acetate (3), which
in turn was converted into the corresponding carbohydrazide 4. Carbohydrazide
4 reacts with a variety of reagents to give different pyrazolopyrimidines (5–12).
Chloromethyl-pyrazolopyrimidine (1) reacts with chloropyridine to give compound
13, which was subjected in a series of reactions to give new compounds 14–20.