{6-Amino-4-[2-[(Z)-hydroxyimino]-2-(4-nitro-phenyl)-ethylamino]-5-nitro-pyridin-2-yl}-carbamic acid ethyl ester
[5-Amino-3-(4-amino-phenyl)-1,2-dihydro-pyrido[3,4-b]pyrazin-7-yl]-carbamic acid ethyl ester
{6-Amino-5-nitro-4-[2-(4-nitro-phenyl)-2-oxo-ethylamino]-pyridin-2-yl}-carbamic acid ethyl ester