2,4-Substituted-3-aza-1-thiabutadienes: a conformational study by dipolmetry
摘要:
Dipole moments of fifteen 2,4-substituted 4-N,N-dimethylamino-3-aza-1-thia(oxa)butadienes were measured in carbon tetrachloride solution. Calculations of molecular moments for five compounds in the sp (C = S and N = C on the same side) and ap conformations were performed according to the bond moment model. A comparison of calculated values with the experimental ones shows that the sp conformation is favoured in the solutions studied, in accordance with the reactivity observed for 4 + 2 cycloadditions.