“…(fi1m) 2 100 cm-' (N,); 6 (60 MHz; CDCl,) 1.33 and 1.55 (2 x 3 H, 2 s, CMe,), 2.8-3. 1 (2 H, m, 1-H (16).-A solution of the disulphonate (4b) (1.75 g) in ethanol (10 ml) and water (5 ml) containing toluene-p-sulphonic acid monohydrate (250 mg) was heated under reflux for 2 h. The reaction mixture was added to CHC1, (200 ml) and saturated aqueous NaHCO, (30 ml). The CHCl, layer was dried (MgSO,) and evaporated to give the diol(l6) which was recrystallised from ethanol (1.4 (17).-The diol ( 16) (400 mg) was treated with acetic anhydride (3 ml) in pyridine (9 ml) for 1 h at room temperature.…”