Synthesis and 1H, 13C and 31P NMR studies of 2,10‐dichloro‐6‐aryloxy‐12H‐dibenzo [d,g] [1,3,2]‐dioxaphosphocin 6‐oxides

The spectral analyses and syntheses of several novel 2,10-dichloro-6-aryloxy/alkyl-12H-dibenzo [d,g] [1,3,2] dioxaphosphocin 6-oxides have been achieved. Long-range coupling [5J(H,P) = 2.4 Hz] was observed between phosphorus and the bridged methylene protons. Based upon NMR data, a tub-like conformation is proposed for the central eight-membered dioxaphosphocin ring. Long-range 2J(P,O,C) and 3J(P,O,C,C) couplins were determined, as were the 31P chemical shifts for sixteen members of these new heterocycles. A variable-temperature study of one member suggested the presence of a tub form as a reasonable candidate for one major conformer but the presence of other forms was also implied.