Potassium hydroxide (2.0 g) was added to a suspension of estrone (1:352 g, 5.0 mmol) and 4-cyano-benzaldehyde (655 mg, 5.0 mmol) in ethanol (40 mL). The resulting orange solution was stirred for 4 hours at room temperature, then acetic acid (5 mL) and water (5 ml) were added (colour changes to yellow). The product precipitated and was filtered off, washed with water (50 mL), ethanol (50 mL) and diethyl ether (50 mL) and dried under high vacuum. Yield: 1.795 g (94%) pale yellow solid. 1H-NMR (DMSO-d6, 400 MHz). δ: 0.91 (s, 3H, —CH3), 1.30-1.66 (m, 5H), 1.82-1.90 (m, 1H), 1.94-2.02 (m, 1H), 2.14-2.22 (m, 1H), 2.30-2.38 (m, 1H), 2.58-2.92 (m, 3H), 6.45 (d, J=2.3 Hz, 1H), 6.51 (dd, J=8.6, 2.3 Hz, 1H), 7.04 (d, J=8.6 Hz, 1H), 7.36 (s, 1H), 7.82 (d, J=8.6 Hz, 2H), 7.90 (d, J=8.6 Hz, 2H), 9.03 (s, 1H, —OH). LRMS (FAB+): 384.1 (100, [M+H]+). LRMS (FAB−): 383.2 (100, [M]−).
