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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 ...
It is dissimilar vs ethers such as tetrahydrofuran. Like enol ethers, 2,5-disubstituted furans are susceptible to hydrolysis to reversibly give 1,4-diketones. Furan serves as a diene in Diels–Alder reactions with electron-deficient dienophiles such as ethyl (E)-3-nitroacrylate. [15]
formula of a carboxylate ion Salts of carboxylic acids are named following the usual cation -then- anion conventions used for ionic compounds in both IUPAC and common nomenclature systems. The name of the carboxylate anion ( R−C(=O)O − ) is derived from that of the parent acid by replacing the "–oic acid" ending with "–oate" or ...
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).
Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the structural nucleus (parent compound) of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.
It exists in equilibrium with the tautomer 2-hydroxyfuran, which serves as an intermediate in the interconversion between the β- and α-furanones. [further explanation needed] The β form is the more stable. The interconversion is catalyzed by base. 2-Furanones can be converted to furans by a two-step process of reduction followed by dehydration.
Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X 2 /X − couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V).
2,3-Dihydrofurans are intermediates in the Feist–Benary synthesis of furans from α-halogen ketones and β-dicarbonyl compounds. [4] The 2,3-dihydrofuran ring can be synthesized by several methods. These routes usually involve cyclization or cycloaddition reactions of carbonyl compounds using metal-containing catalysts.