The chemistry of the steroid 17@-carboxylic acids derived from 16, 17a-disubstituted corticosteroids was investigated with respect to thiol ester formation. Major quantities of 17- spiro byproducts were observed in the reactions of 16-methyl-17a-acyloxy acids, and the degree of 17-ester participation leading to these structures was dependent on the carboxylate activating group used and stereochemistry at C-16. Diethyl phosphate mixed ...
![(8S,10S,11S,13S,14S,16S)-9-fluoro-11,17-dihydroxy-10,13,16-trimethyl-3-oxo-6,7,8,11,12,14,15,16-octahydrocyclopenta[a]phenanthrene-17-carboxylic acid结构式](https://image.chemsrc.com/caspic/040/37926-75-3.png)
![(diethyl phosphoric) (6S,8S,9R,10S,11S,13S,14S,16R,17R)-6,9-difluoro-11-hydroxy-10,13,16-trimethyl-3-oxo-17-(propionyloxy)-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthrene-17-carboxylic anhydride结构式](https://image.chemsrc.com/caspic/184/73205-12-6.png)