Furans

What are furans? Furans are heterocyclic organic compounds consisting of a 5-membered aromatic ring with four carbon atoms and one oxygen atom. furan is a colorless, highly volatile and flammable liquid with a boiling point of 31 ºC. It is also slightly soluble in water, soluble in common organic solvents, and with a dipole moment … Read more

Isoxazoles, isothiazoles and their benzoderivatives

What are isoxazoles, isothiazoles and their benzoderivatives? Isoxazole and isothiazole are liquids of boiling point 95 and 113 ºC, respectively. There are several natural isoxazoles with significant pharmacological activity, for example, muscimol, which is a fungus (Amanita muscaria) with psychotropic effects. Two types of isoxazoles and benzofused isothiazoles can occur. Thus, monocyclic systems and their … Read more

Benzo-fused 5-membered heterocycles

What are benzo-fused 5-membered heterocycles? Condensed 5-membered heterocycles are the heteroatoms resulting from the fusion of a benzene ring and a 5-membered heterocycle. The main ones are those where the fusion is performed on the 2-3 bond of the heterocycle. The description of these 3 heterocycles (indole, benzofuran and benzothiophene), from the point of view … Read more

Five-membered rings with one heteroatom

What are five-membered rings with one heteroatom? Five-membered rings with one heteroatom are pentagonal heterocycles that have one atom in the ring other than carbon. It is one of the most relevant groups of heterocyclic compounds, and the three most notable are: pyrrole, furan and thiophene. fig-01 These heterocycles can be considered as aromatic, to … Read more

Bibliographic Sources in Organic Chemistry

Knowledge and management of information sources is one of the basic pillars for the development of teaching and research work. It is worth noting that the search, fast, reliable and as exhaustive as possible of the results generated by other research groups, currently or in the past, is essential for the development of scientific activity. … Read more

Oxazoles and thiazoles

What are oxazoles and thiazoles? Oxazole and thiazole are heterocycles that are closely related to furan and thiophene. The oxazole ring system is almost not found in nature and has no significant natural derivatives. In contrast, thiazole is very common in natural products, for example, vitamin B1 (thiamine) contains a pyridine ring and a thiazole ring. … Read more

Thiophenes

What are thiophenes? Thiophenes are heterocyclic organic compounds, consisting of a 5-membered aromatic ring with four carbon atoms and a sulfur atom. Thiophene is a liquid with a boiling point of 84 °C, found in coal tar. It occurs as a contaminant of benzene, when obtained from coal tar. fig-01 Thiophene is an electron-rich aromatic … Read more

Six-membered rings with one oxygen

What are hexagonal heterocycles with one oxygen? Because the neutral divalent oxygen atom cannot replace the CH group of the benzene ring (it would need valence 3). Therefore, the existence of neutral oxygenated compounds with a constitution analogous to pyridine is not possible. The cyclic, unsubstituted, uncharged system with two double bonds is called a … Read more

Electrophilic Aromatic Substitution (SEAr)

What is the electrophilic aromatic substitution reaction (SEAr)? These are characteristic reactions of the aromatic ring of benzene and derivatives, involving the substitution of one hydrogen of the ring by another group that has an electrophilic character (E⊕), is positively charged or is a reactant capable of forming a bond with two electrons of the … Read more

Three-membered heterocycles

What are three-membered heterocycles? The chemistry of three-membered heterocycles is dominated by angular tension, which leads to high reactivity. Attack by a nucleophile on a ring carbon, heating or irradiation can result in ring opening. Therefore, three-membered heterocycles are abnormally reactive molecules, and very useful as intermediates in synthesis. Oxiranes (epoxides) Oxiranes or epoxides are … Read more