18-Methyl-19-nor-20-keto steroids of the formula ##STR1## wherein R.sub.1 and R.sub.2 collectively are an oxygen atom, or each is hydrogen, or one of R.sub.1 and R.sub.2 is hydrogen and the other is hydroxy, and R.sub.3 is a ketonic oxygen atom or two hydrogen atoms, possess CNS-depressant activity, especially anesthetic-narcotic activity.
                            公式为##STR1##的18-甲基-19-去氢-20-
酮类固醇,其中R.sub.1和R.sub.2共同是氧原子,或者每个都是氢原子,或者R.sub.1和R.sub.2中的一个是氢原子,另一个是羟基,而R.sub.3是一个酮氧原子或两个氢原子,具有中枢神经系统抑制活性,特别是麻醉镇痛活性。