Preparation and Some Properties of Isomeric Carboaryloxyaminoanilines

Heating 2-aminophenylurethane above its melting point causes loss of alcohol and formation of o-phenyleneurea [Ber., 12, 1296 ( 1879)]. Attempts to acylate the hydroxyl group of 2-carbophenoxyaminophenol splits off phenol and closes the benzoxazolone ring [J. Am. Chem. Soc., 56, 1590 (1934)], as shown below. It is now found that when 2-carliophenoxyaminoaniline is heated above its melting point phenol is lost and o-phenyleneurea is formed. If the same aminoaniline derivative is dissolved in caustic alkali solution and the resulting liquid is acidified with dilute mineral acid the cyclic urea indicated above is precipitated. The formation of this urea is favored by the presence of certain substituents in the carbophenoxy radical. Thus, 2-carbo-(2-chlorophenoxy )- aminoaniline decomposes into o-phenylcneurea and 2-chlorophenol in attempts to crystallize the aniline from alcohol. The isomeric meta and para derivatives are much more stable and do not form cyclic ureas under these conditions. The carbophenoxyaminoanilines required in this work could not be prepared directly from the corresponding phenylenediamines, but were obtained by reduction oi the related carboaryloxyaminonitrobenzenes in acid mixtures. The products were further characterized by study of their simple and mixed diacyl derivatives