Synonyms: 9b,10a-Pregna-1,4,6-triene-3,20-dione, 6-chloro- (7CI,8CI);1,6-Dehydro-6-chlororetroprogesterone; 6-Chloro-1,6-dehydroretroprogesterone;6-Chloro-9b,10a-pregna-1,4,6-triene-3,20-dione; Retroid; Ro 4-8347;Pregna-1,4,6-triene-3,20-dione,6-chloro-, (9b,10a)- (9CI)