Abstract: In a method proposed to investigate conjugative interactions between second-row elements (S, P) amd a n-electron system, barriers to amide rotation have been measured using NMR line-shape methods, for N-acetyl-4-X (hetero)-1, 4-dihydropyridines (X= SOz, 7; P (0) OCH3, 13; C (CH3) 2, 6 (reference)) as well as the dihydro (84 and tetrahydro (9) derivatives, respectively, of 7. It is suggested that such interactions would stabilize the ...
