Ethylene Glycol → 3beta-Iodoandrost-5-en-17-one-17-ethyleneketal

Participants

Reaction Steps

More specifically, 3β-iodoandrost-5-en-17-one (11) (11.83 g, 29.7 mmol), ethylene glycol (20 ml) and p-toluene sulfonic acid (200 mg) in benzene (250 ml) were refluxed under a Dean-Stark trap for 72 hrs. The solution was washed with saturated sodium bicarbonate, water, then dried over magnesium sulfate. Evaporation and recrystallization from ether afforded 11.5 g (87.3%) of 3β-iodoandrost-5-en-17-one-17-ethyleneketal (12): mp 140°-141° C., IR (KBr): 3010, 2940, 1470, 1425, 1375 cm-1 ; 1H NMR (CDCl3): δ5.44 (brd J=6 Hz, 1H, H-6), 3.91 (s, 4H, ketal), 1.07 (s, 3H, C-19 Me), 0.88 (s, 3H, C-18 Me); MS (m/e): 442 (M+, 1), 380 (35), 315 (57), 253 (67), 227 (11), 105 (24), 99 (100), 91 (35), 55 (27), 41 (33).

Provenance & Evidence