The disubstitution effects of X and Y in 1-(Y-phenyl)-3-(X-phenyl)-2, 3-dihydro-1 H-naphth [1, 2-e][1, 3] oxazines on the ring-chain tautomerism, the delocalization of the nitrogen lone pair (anomeric effect), and the 13C NMR chemical shifts were analyzed by using multiple linear regression analysis. Study of the three-component equilibrium B⇌ A⇌ C revealed that the chain⇌ trans (A⇌ B) equilibrium constants are significantly influenced by the inductive ...