P. Nair, R. Srinivasan, K. Venkataraman
1960
Citations
0
Influential Citations
5
Citations
Journal
Tetrahedron
Abstract
Abstract o -Hydroxyarylamides react readily with 2,4-dinitrochlorobenzene in presence of bases to give the N-2,4-dinitrophenyl derivatives. The reaction appears to proceed by a direct displacement of the halogen by the amide nitrogen involving intramolecular nucleophilic catalysis by the phenoxide oxygen; but a Smiles rearrangement is not completely excluded. The N-dinitrophenyl derivatives are stable to boiling hydrochloric acid, but are hydrolysed easily by aqueous sodium carbonate or hydroxide. Condensation with dinitrochlorobenzene, followed by mild alkaline hydrolysis, is a useful procedure for determining the constitution of azoic coupling components of the Naphtol AS type. Thus Naphtol AS-RS and AS-KN have been shown to be the 4-chloro-2-methoxy-5-methylanilide of 2-hydroxy-3-naphthoic acid and the α-naphthylamide of 3-hydroxydibenzofuran-2-carboxylic acid respectively.