Steroid Borates I. Structural Considerations

It has been found that alkaline aqueous solutions of various boric acids readily solubilize steroid molecules containing a cis-1,2-diol grouping. Both triamcinolone (9α-fluoro-l6α-hydroxy-prednisolone) and its synthetic precursor “F-3” (9α-fluoro-16α-hydroxy-hydrocortisone) demonstrate this property. It is proposed that the structure of the product formed between the steroid and alkaline borate involves two steroid molecules and one tetrahedral boron atom. Some physicochemical data are presented to substantiate this view.