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.
Indolizine is a heterocyclic compound and an isomer of indole. Indolizine derivatives are widely used in natural products and synthetic drugs. Indolizine has various pharmacological activities, such as anti-tuberculosis, anti-cancer, anti-fungal, anti-bacterial, antioxidant and anti-inflammatory.