Some Chemical and Physical Properties of the Crystalline Follicular Ovarian Hormone

Abstract

The quantity of the earlier preparations of the crystalline hormone was insufficient for much chemical work. Three samples which were carefully assayed showed a potency exceeding 3000 rat units per milligram. The melting point of the crystals of preparations No. 119 and No. 143 was 243°C. (uncor.).

When larger quantities of the crystals became available an investigation of the chemical and physical properties of the compound was begun. The data given in Table I were obtained by micro methods which had been studied with known compounds.

The melting point was taken by the open beaker method. The corrected temperature is approximately 6° higher. The molecular weight determined by the Rast micro method gives values which agree with the values calculated from the Iodine number upon the assumption that there is one double bond in the molecule. The Iodine number was determined at 0°C. in the dark by a micro modification of the Hanus method. The hormone was acetylated with acetic anhydride in pyridine and the weight obtained indicated two hydroxyls. The molecular weight of the recrystallized derivative confirmed this. The esterification of 2 alcoholic radicals would increase the molecular weight by 84 gm. which, added to the average value obtained by the Rast method (274 + 84 = 358), gives a value close to those experimentally determined.

The crystals were analyzed for C and H by Pregl's micro combustion method. Average, C 79.69%; H 8.49%; O 11.82%. These data give an empirical formula of C₁₈H₂₃O₂ with a molecular weight of 271, which corresponds with the data of the table.