Abstract
When the Tschugaeff reaction is carried out in methylene chloride, the color developed becomes brighter. Of the colored substances formed, the red colored substance formed with cholesterol tends to be discolored by sunlight. This substance contains zinc and purification with removal of zinc gives cholesteryl acetate. In the Tschugaeff reaction, red substance (R) is formed from the reagents alone, acetyl chloride and zinc chloride. Warming the chloroform solution of various steroids with this red substance results in the formation of a substance whose absorption spectra in the range of 320-600mμ are the same as that in the case of coloration by the Tschugaeff reaction. For example, the product obtained by reaction with ergosterol colors green and its absorption maximum is the same as that of the product from the Tschugaeff reaction. Warming of the chloroform solution of cholesterol or ergosterol and the red substance (R) results in dehydration and rearrangement of the double bond, giving a hydrocarbon containing zinc from cholesterol. It was assumed that when the B-ring in unsaturated steroid is active, it undergoes addition with (R) and forms one of the colored products from the Tschugaeff reaction. Cortisone acetate, which does not give any marked coloration by the Tschugaeff reaction, afforded two kinds of crystalline substances in which the double bond had undergone rearrangement. The reaction product from cholesterol afforded 3, 5-cholestadiene and 3, 3′-bis-2, 4-cholestadienyl.
