THE PRINCIPAL CONFORMATIONS OF SOME ORTHO-SUBSTITUTED DIPHENYL ETHERS

A study of the nuclear magnetic resonance, infrared, and ultraviolet spectra showed that some doubly and triply ortho-substituted diphenyl ethers adopt, principally but not exclusively, the "H-inside" conformation, while the quadruply ortho-substituted 7-(4′-carbomethoxy-2′,6′-dinitrophenoxy)metameconine (V) adopts the "methoxy-inside"conformation. Interconversion of conformational isomers is extremely fast. Reduction of methyl 4-methoxy-3-nitrobenzoate with tin and hydrochloric acid gave methyl 3-amino-2-chloro-4-methoxybenzoate.