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The isostere concept was formulated by Irving Langmuir in 1919, [3] and later modified by Grimm. Hans Erlenmeyer extended the concept to biological systems in 1932. [ 4 ] [ 5 ] [ 6 ] Classical isosteres are defined as being atoms, ions and molecules that had identical outer shells of electrons, This definition has now been broadened to include ...
Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. [3] Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one ...
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature.
Furfural is used to make other furan derivatives, such as furoic acid, via oxidation, [30] and furan itself via palladium catalyzed vapor phase decarbonylation. [ 4 ] There is a good market for value added chemicals that can be obtained from furfural.
Included are pyridine, thiophene, pyrrole, and furan. Another large class of organic heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinoline, benzothiophene, indole, and benzofuran, respectively. The fusion of two benzene rings gives rise to a third ...
Thiophene is a heterocyclic compound with the formula C 4 H 4 S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. ...
Pyrrole has a nutty odor. Pyrrole is a 5-membered aromatic heterocycle, like furan and thiophene. Unlike furan and thiophene, it has a dipole in which the positive end lies on the side of the heteroatom, with a dipole moment of 1.58 D. In CDCl 3, it has chemical shifts at 6.68 (H2, H5) and 6.22 (H3, H4).
The furan ring may be fused in various ways, producing several different isomers. The parent compounds of the most common isomers are psoralen and angelicin . Derivatives of these two compounds are referred to respectively as linear and angular furanocoumarins, [ 4 ] so called since they exhibit a linear or angular chemical structure.