Antimicrobial activity of basic cholane derivatives, VIII.
Two series of new compounds derived from deoxycholic acid have been synthesized: 3,12-dioxo-5 beta-cholan-24-N-substituted amides and their 3 beta-amino and 3 beta-N-alkylamino derivatives. The first series of five compounds 1-5 carries at C-24 the residue of benzylamine, morpholine, diethanolamine, N,N-diethyl-ethylenediamine, and N-methylpiperazine. The second series of twenty compounds 1A-D - 5A-D was prepared by means of reductive amination starting from the compounds of the first series. This reaction proved to be regioselective and stereospecific: it attacks only C-3 of the steroid moiety and introduces the following axial beta-oriented substituents: amino, methylamino, ethylamino, and benzylamino. The compounds of the first series showed moderate scattered antimicrobial activity; while introduction of the 3 beta-amino and 3 beta-N-alkylamino residue greatly increased activity towards Gram (+) strains; even yeast and fungi appear to be sensitive towards this last series of compounds. The results have been discussed with respect to the nature of the substituents both at C-3 and C-24, the highest activity being associated to the hydrophobicity of these residues.