3alpha-Hydroxy-20-oxo-5alpha-pregnan-21-yl hemisuccinate (8) was produced by partial acylation of 3alpha,21-dihydroxy-5alpha-pregnan-20-one (14). 3alpha-Fluoro-5alpha-pregnan-20-one (9) was prepared by treatment of 3beta-hydroxy-5alpha-pregnan-20-one (11) with DAST and by solvolysis of tosylate 12 with tetrabutylammonium fluoride. A behavioral test on mice was performed using 3alpha-hydroxy-5alpha-pregnan-20-one (1) and compounds 8 and 9. Compound 8 was found to be inactive, while the fluoro derivative 9 selectively reduced aggressive behavior in mice more than the corresponding 3alpha-hydroxy compound 1; locomotion and other behavioral features were not affected.