Constitution of Cholesterol

Abstract

IT is not too much to say that work published this month¹ has resolved all dubieties in regard to the main outlines of the molecular structure of the sterols and bile acids, and unquestionably the Wieland-Dane formula is correct. In addition to the change in the position of the hydroxyl group which was mentioned in my letter of October 8 a further modification of current views is necessary in order to make the pieces of the puzzle fit together. Lithobilianic acid and isolithobilianic acid must be stereoisomerides and not structural isomerides as usually assumed and the seat of this persistent type of isomerism is doubtless C—8 of Wieland-Dane's formula. Thus in a cis-series we have lithobilianic acid, dihydrocholesterol, the Abderhalden-Diels dibasic acid; and in a trans-series, coprosterol and isolithobilianic acid. Interchange of the isomerides occurs when a carbonyl group is attached to positions 8 or 9 as in deoxybilianic acid and ketostadonic acid. Stereoisomerism also arises as the result of the disposition of groups round position 5.