GB564610A - A method of introducing an amino group into aromatic compounds - Google Patents

Abstract

An amino group is introduced into an aromatic compound by reaction of the aromatic compounds, in presence of strong sulphuric acid and a metal salt, with a compound of the formula R-CH2-NO2, in which R is H, or an alkyl, aryl or aralkyl group, e.g. nitro- or dinitro-methane or ethane or nitropropane. Aliphatic nitro compounds may be replaced by the isomeric hydroxamic acids, thus dinitroethane may be replaced by hydroxam-oxalic acid. A salt of iron or vanadium in amount wholly dissolved in the acid is preferred. The process may be used for introducing amino groups into dyestuffs, e.g. of the anthraquinone group or indigoids and for analytical purposes when the presence of a benzene or naphthalene ring is suspected, the amino group introduced being detected by diazotisation. Examples give the preparation of sulphanilic and metanilic acid from benzene, aminonaphthalenesulphonic acid from naphthalene, aminoanisolesulphonic acid from anisole, aminophthalic acid from phthalic anhydride, aminosulphobenzoic acid from benzoic acid, aminoanthraquinone from anthraquinone, a -aminoalizarin from alizarin, aminobenzanthrone from benzanthrone, aminobenzoic acid from phenylnitromethane, a black dyestuff from dibenzanthrone. An amino group can also be introduced into anthraquinonesulphonic acid, chloroanthraquinone, phenanthraquinone, and a dark navy-blue dyestuff is obtained from isoviolanthrone, brown dyestuffs from pyranthrone, and grey dyestuffs from indigo and thioindigo.