Chapter 2 - Compounds Containing a Five-Membered Ring with One Hetero Atom of Group VI; Oxygen

Abstract

Publisher Summary The uncondensed and unreduced furan nucleus occurs in a few constituents of essential oils. They are commonly plant products; a few are of fungal origin. Furfural is manufactured on a large scale by the acid hydrolysis of oak hulls (husks), and its reductive and other transformations afford useful intermediates and industrial solvents. The chemistry of the furan group of compounds is better understood from the study of its substitution products, such as alkyl- and aryl-furans, halogenofurans, furansulfonic acids, nitrofurans, amino- and cyano-furans, oxodihydrofurans or butenolides (hydroxyfurans), furfuryl alcohol and related compounds, aldehydes, ketones, carboxylic acids, dihydrofurans, and tetrahydrofurans. The polyene derivatives of furan have been studied, on the one hand as objects of spectroscopic investigation as such and as halochromic materials, and on the other as sources of difficulty accessible aliphatic compounds by hydrogenation, followed by opening of the furan ring. General methods of synthesis, properties and reactions are also discussed for benzo[b]furans and their hydrogenated products such as alkyl- and aryl-benzofurans, halogenobenzofurans, nitro- and amino-benzofurans, hydroxybenzofurans, alcohols, aldehydes and ketones, benzofuran carboxylic acids, The compounds of the series isobenzofuran (benzo[c]furan; 3,4-benzofuran) and its derivatives are much less stable and far less numerous than those of the 2,3-benzofuran (benzo[b]furan) group.