2177 more polar solvents, but this material was not used for the following transformation.The benzene eluted 1.5-g. sample was dissolved in acetic acid and shaken overnight at room temperature with 0.4 g. of platinum oxide catalyst. The product was saponified with 5% aqueous ethanolic potassium hydroxide for 24 hr., concentrated, and water added. Extraction with ether left no residue and acidification of the ether solution followed by extraction with ether, extraction with bicarbonate, acidification, and re-extraction with ether furnished, after drying and evaporation, 0.86 g. of acid.A 0.55-g. sample of this acid was esterified with ethereal diazomethane solution and the crude ester was fractionated by distillation affording 0.31 g. of material with b.p. 60°/ 0.01 mm. and 0.20 g. with b.p. 93°/0.01 mm. The lower boiling fraction exhibited no infrared hydroxyl absorption, a strong band at 5.76 µ, a shoulder at 5.85 µ and a relatively weak band at 6.08 µ.

A series of Zaffaroni-type solvent systems has been chosen which encompasses the entire range of steroidal polarities commonly encountered. Based on calculations from values given in this paper, the practical chromatographic range of each solvent system can be quantitatively described. The mobility of a steroid in each system can be estimated by inspection of its structure, thus permitting the choice of a suitable solvent system without literature references or experimentation.The method is developed in detail for the pregnane series and illustrated by application to a related series of compounds.The method is general and can be extended to include other solvent systems and steroidal types.

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