High-field ¹H NMR studies of prostaglandin H₂ and its decomposition pathways

Prostaglandin H₂ displays at 500 MHz a detailed ¹H-NMR in which all methylene groups are non-equivalent in C₆D₆ solution. The spectrum was assigned by analogy to isosteric structures. The dissymmetric perturbation and steric hindrance of the bicyclo [2.2.1] core caused by the side-chains provides a rationale for the selective fragmentations which PGH₂ undergoes. Purified PGH₂ is considerably more robust than previous literature accounts suggest. The following transformations were monitored by ¹H-NMR: 1) OO bond cleavage by Ph₃P, 2) aqueous media fragmentation to PGE₂ and PGD₂, 3) base catalyzed fragmentation to ketoaldehydes, and 4) thermolysis attempts.