| 摘要 |
<p>The invention comprises 17b -acyloxy-13b -n-propyl - 4,5 - seco - gon - 5 - one derivatives of the general formula <FORM:1003086/C2/1> in which Ac represents the acyl group derived from an organic carboxylic acid; R represents a cyclic ketal grouping and a double bond lies either between the 9(10)-positions, or between the 9(11)-positions and a methyl group is present in the b -orientation of the 10-position, or alternatively R represents the oxygen atom = O of a keto group and a double bond lies between the 9(11)-positions and a methyl group is present in the 10b -position and processes for the preparation thereof wherein a 17b -acyloxy-13b -n - propyl - 4,5 - seco - gon - 9 - ene - 3,5 - dione is ketalized to form the corresponding 3-cyclic ketal derivative, treating the 3-cyclic ketal derivative thus obtained with a methylating agent in the presence of an enolizing agent to form the corresponding 3-cyclic ketal of 17b -acyloxy - 10b - methyl - 13b - n - propyl - 4,5 - seco - gon - 9(11) - ene - 3,5 - dione which is subjected to acid hydrolysis to liberate the 3-ketal group. Ketalization may be effected with methyl-ethyl dioxolan in the presence of an inert solvent and methylation with methyl iodide in toluene. Specification 979,892 also is referred to.</p> |
