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.
Dioxolane is a heterocyclic acetal with the formula (CH2)2O2CH2. It is related to tetrahydrofuran by exchanging an oxygen for the CH2 group. The isomer 1,2-dioxolane (in which the two oxygen centers are adjacent) is a peroxide. 1,3-Dioxolane is used as solvent and comonomer in polyacetal. The dioxolane-type and their hydrogenolysis can provide very valuable partially protected building blocks either for oligosaccharide syntheses or sugar transformations.
Tetrahydroisoquinoline is an organic compound with the chemical formula C9H11N. It is classified as a secondary amine, obtained from isoquinoline by hydrogenation. The tetrahydroisoquinoline moiety forms the backbone of several natural, synthetic and semi-synthetic drugs approved for the treatment of cancer, pain, gout and various neurodegenerative diseases.