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.
Pyrazolidine is a saturated organic heteromonocyclic parent. Pyrazolidines are important synthetic intermediates in organic synthesis. Pyrazolidine compounds are valuable heterocyclic compounds due to their powerful biological properties.