A solution of 4-amino-N-(1,1-dimethylethyl)-3-oxoandrosta-4,6-diene-17β-carboxamide (0.9 g, 2.34 mmole) in acetic anhydride (3 mL) and pyridine (6 mL) was stirred overnight at room temperature. Water was added and the mixture was stirred for 3 hours. The solids were collected by filtration to give a brown solid which was purified by flash chromatography (hexane-50% ethyl acetate, ethyl acetate) to give 4-acetamido-N-(1,1-dimethylethyl)-3-oxoandrosta-4,6-diene-17β-carboxamide (0.29 g, 30.4%, diethyl ether-hexane). IR 3442, 3382, 1664, 1616 cm-1 ; MS (CI) m/z 427 (100%, M+ +1); (EI) m/z 426 (65%, M+), 57 (100%); 1H NMR (CDCl3) δ 0.78 (3H, s, C18 -Me), 1.13 (3H, s, C19 -Me), 1.35 (s, 3× tBu-Me's), 2.14 (s, Ac-Me), 5.13 (1H, s, NHCOBu), 6.16 (2H, s, C6 -H+C7 -H), 7.12 (1H, NHAc); 13C NMR (CDCl3) δ 124.65, 124.89, 139.95, 153.20, 168.74, 171.44, 194.93. This compound has the following structure: ##STR4##
