Features of the reaction of 1-amino-2-nitroguanidine with isatins. Synthesis of [1,2,4]triazino[5,6-b]indoles

Reactions of 1-amino-2-nitroguanidine with isatins leading to the formation of new β-(2-nitro)guanidinohydrazones of isatin, which exist as E / Z -isomers in regards to the azomethine fragment, were studied. It was found that the conditions of the reactions of 1-amino- 2-nitroguanidine with isatins affect the geometry of the formed hydrazones. Conditions for the cyclization of the obtained ( Z )-β-(2-nitro)- guanidinohydrazones leading to 3-nitroimino-containing [1,2,4]triazino[5,6- b ]indoles were proposed.