Synthesis of novel α-aminoecdysteroids via regio- and stereoselective oximation/hydrogenation of 20-hydroxyecdysone derivatives

Oximation of 20-hydroxyecdysone oxo derivatives proceeds regio- and stereoselectively and provides (E)-configured oximes in quantitative yields. The Ni–Ra-catalyzed hydrogenation of the oximes affords novel α-aminoecdysteroids with the unchanged 14α-hydroxy-7-en-6-on native chromophore of ecdysteroids. The structures of synthesized compounds were confirmed by the means of homo- and heteronuclear one-dimensional and two-dimensional 1H and 13C NMR spectroscopy and X-ray crystallography.