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.
Phthalazine is a heterocyclic compound with the molecular formula C8H6N2 composed of a benzene ring fused with a pyridazine ring. Phthalazine and its derivatives do not exist in nature. Phthalazines are used as starting materials for organic synthesis. Studies have found that phthalazine has a variety of physiological activities, such as anti-cancer, antibacterial, anti-inflammatory and so on. The synthesis of phthalazine compounds with novel structures and better biological activities has become a research hotspot in recent years.