Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom with the molecular formula C4H4S. Thiophene is aromatic and is very similar to benzene; electrophilic substitution reaction is easier than benzene, and it is mainly substituted at the 2-position. Thiophene ring system has certain stability to oxidant.
Pyrazolopyrimidine scaffolds are one of the most important heterocyclic compounds in drug discovery. This scaffold has various biological activities, among which anticancer is an important one.