19-Nor-17.alpha.-pregna-1,3,5(10)-trien-20-yne, 21-chloro-3,17-dimethoxy- 19-Norpregna-1,3,5(10)-trien-20-yne, 21-chloro-3,17-dimethoxy-, (17.alpha.)- 7548-44-9 BDH 2700 NSC84053