Synthesis of Novel Dipyrazolopyrimidine Fused Heterotricyclic Compounds

Novel fused heterotricyclic compounds 3–6 containing two different dipyrazolopyrimidine framework were prepared from 1a–1d . The reaction of 1 with K 2 CO 3 in DMSO or NaH in DMF led to the formation of 2 or 3 , respectively, which reacted further to afford 6 or 5 , respectively