“…It was found that addition of urea greatly facilitated denitrosation by trapping NO+ generated in this reaction .4 Mass spectral analysis of 5 showed it to contain 66.5% D4, 25.3% D3, 4.4% D2, and 1.7% D, the balance (2.1%) being undeuterated. The pmr spectrum of 5 exhibited two doublets (/gem = 14 Hz) at 2.35 and 2.76 which are due to the axial and equatorial protons at C-3 and C-5. This is consistent with the a positions being the sites of exchange and is in marked contrast with the pmr spectrum of the undeuterated compound 1 which exhibits an envelope absorption in the 2.2-3.7 region.…”