C#C.[CH2:3]([Li])[CH2:4]CC.C(O[C@@H:12]1[C@H:17]2[C@H:18]3[C@H:28]([CH2:29][CH2:30][C@:15]2([CH3:16])[C:14](=[O:33])[CH2:13]1)[C@:26]1([CH3:27])[C:21]([CH:22]=[C:23]([O:31]C)[CH2:24][CH2:25]1)=[CH:20][CH2:19]3)(=O)C.[Cl-].[NH4+]>O1CCCC1.C(OCC)(=O)C>[C:3]([C@:14]1([OH:33])[CH:13]=[CH:12][C@H:17]2[C@H:18]3[C@H:28]([CH2:29][CH2:30][C@:15]12[CH3:16])[C@:26]1([CH3:27])[C:21](=[CH:22][C:23](=[O:31])[CH2:24][CH2:25]1)[CH2:20][CH2:19]3)#[CH:4]Acetylene is introduced at 0° C. for 45 minutes into 200 ml of butyllithium solution (1.6 molar in hexane) in 600 ml of tetrahydrofuran. Then, 20.0 g of 15α-acetoxy-3-methoxyandrosta-3,5-dien-17-one in 400 ml of tetrahydrofuran is added thereto. After 2 hours, the mixture is gently combined with saturated ammonium chloride solution, diluted with ethyl acetate, washed with water, dried, and concentrated under vacuum. At room temperature, 14 ml of concentrated hydrochloric acid is added dropwise to the crude product in 400 ml of methanol and 50 ml of water. After 1.5 hours, the reaction mixture is stirred into ice/water. The thus-precipitated product is suctioned off, washed with water, dissolved in ethyl acetate, dried, and concentrated under vacuum. The crude product is chromatographed on silica gel with a hexane-ethyl acetate gradient, thus obtaining 9.5 g of 17α-ethynyl-17β-hydroxyandrosta-4,15-diene-3-one, mp 206.4° C. (from acetone/hexane).
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