NOVEL AND REGIOSPECIFIC SYNTHESIS OF 2-AMINO ESTROGENS VIA ZINCKE NITRATION

Article abstract of DOI:10.1016/0039-128X(83)90033-8

An efficient synthesis of 2-aminoestrone (14), 2-aminoestradiol (15), 2-amino-16α-hydroxyestrone (16) and 2-aminoestriol (17) is described. 2,4-Dibromo estrogens 1 - 4 were regiospecifically converted to the corresponding 2-nitro-4-bromo derivatives 5 - 8 in quantitative yields, with Zincke nitration using sodium nitrite.Catalytic hydrogenation of the 2-nitro-4-bromides 5 - 8 over palladium-on-charcoal gave directly the desired 2-amino estrogens 14 - 17 in high yields.The 2-amino compounds 15 and 17 were also obtained by the reduction of the corresponding 2-nitro-4-bromides 6 and 8 with sodium borohydride in the presence of palladium chloride.