Reaction Steps
Borane-tetrahydrofuran complex (1 M in THF) (3 mL, 3 mmol) was added dropwise to the product from example 45 (0.33 g, 1.18 mmol) in dry THF (4 mL) under an atmosphere of nitrogen. The reaction mixture was heated at 85° C. for 3 hours then cooled and quenched by the addition of methanol (1 mL). The reaction mixture was then concentrated in vacuo and the residue suspended in 6N HCl (aq) (10 mL) and heated to 60° C. for 1.5 hours. The reaction mixture was cooled and extracted with diethyl ether (2×10 mL). The aqueous layer was rendered basic (pH 9-10) by addition of solid potassium carbonate before re-extracting with dichloromethane (2×15 mL). The dichloromethane extracts were dried over anhydrous magnesium sulphate, filtered and concentrated in vacuo to give the crude products as a clear oil. Purification by column chromatography on silica eluting with ethyl acetate:pentane (1:10) yielded the two title compounds as single diastereomers. Example 46A: clear oil (0.10 g, 0.38 mmol, 32%): 1H NMR (CDCl3, 400 MHz) δ: 1.00 (m 6H), 1.60 (bm, 3H), 1.85 (m, 1H), 2.25 (bt, 2H), 2.35 (s, 1H), 2.45 (m, 1H), 2.60 (m, 1H), 2.65 (m, 1H), 3.70 (s, 1H), 3.80 (s, 3H), 4.80 (s, 1H), 6.80 (d, 1H), 7.00 (m, 2H), 7.25 (m, 1H). LRMS (APCl): m/z 264 (M−H+). Example 46B: clear oil (0.10 g, 0.38 mmol, 32%): 1H NMR (CDCl3, 400 MHz) δ: 0.90 (t, 3H), 1.00 (t, 3H), 1.60 (bm, 4H), 1.80 (bs, 1H), 2.00 (bs, 1H), 2.35 (bs, 2H), 2.85 (bd, 1H), 2.95 (bd, 1H), 3.60 (s, 1H), 3.80 (s, 3H), 4.60 (s, 1H), 6.80 (d, 1H), 6.95 (s, 2H), 7.25 (t, 1H). LRMS (APCl): m/z 264 (MH+).
