A number of steroidal as well as non-steroidal ketones have been converted into the corresponding cyclic ethylene (1.3-oxathiolane) and trimethylene (1, 3-oxathiane) hemithioketals by employing either azeotropic distillation or an exchange method with the corresponding hemithioketal of acetone and continuous removal of acetone. Formation of the hemithioketals of A'-3-ketosteroids appears to be accompanied by a shift of the 4, 5- ...
![4-ethoxy-3-nitro-N-[4-(propanoylamino)phenyl]benzamide Structure](https://image.chemsrc.com/caspic/331/5838-79-9.png)