Quinones as reagents for the dehydrogenation of cholesteryl acetate to pro‐vitamin D

Abstract 1,4‐Quinones, when heated with cholesteryl acetate in sealed tubes at 120 to 135° for 6 to 8 hours, were found to partially dehydrogenate the sterol ester to a pro‐vitamin D (probably 7‐dehydro‐cholesteryl acetate). The crude products, after the removal of hydroquinones, quinhydrones and unreacted quinones, were irradiated for 4 hours with ultraviolet light produced by a quartz‐mercury lamp and were found to acquire antirachitic properties. 1,2‐Quinones, when used in the above reaction, gave doubtful results. Aliphatic and aromatic di‐ketones, such as diacetyl, benzil, anthraquinone and phenanthroquinone, were not able to dehydrogenate the sterol ester to pro‐vitamin D, since their products, after irradiation, acquired no antirachitic properties.