17-alpha-Chlorethynyl-19-nor-delta(sup 5(10))androsten-17-beta-ol-3-one 19-Nor-17-alpha-pregn-5(10)-en-20-yn-17-ol, 21-chloro- 21-Chloro-19-nor-17-alpha-pregn-5(10)-en-20-yn-17-ol RC8964420