Contragestational agents. 1. Steroidal-O-aryloximes

: The preparation of a series of O-aryloximes of various steroids by two different routes is described. These compounds were prepared by reacting a keto steroid with a substituted O-arylhydroxylamine in the presence of an acid catalyst or, alternatively, by the reaction of a steroidal oxime with a substituted aryl halide in the presence of a suitable base. These compounds were examined for their ability to interrupt postimplantive gestation in female rats. The most significant contragestational activity was seen with compounds in which the basic steroid structure was a 5alpha-androstane and the 3-oxime was of the p-nitrophenyl series. One of the most active compounds in the series (16) was shown to have the ability to terminate pregnancy, when orally administered to rats at 2.5 mg/kg on days 9-12 of gestation. This compound was found to be devoid of androgenic activity at this dose level.