Synthesis of pyridazine derivatives through the unexpected intermediate 5‐amino‐ 4‐cyano ‐2,3‐dihydro‐furan‐2,3‐disulfonic acid disodium salt

An unexpected compound (5‐amino‐4‐cyano‐2,3‐dihydrofuran‐2,3‐disulfonic acid disodium salt, 4 ) was isolated from the reaction of glyoxale bis hydrogen sulfite disodium salt with malononitrile. Its structure was undoubtly identified through crystal structure analysis. Compound 4 was highly stable and it was isolated easily and in a very high yield. Its reactivity was studied in the reactions with some hydrazine derivatives in order to obtain different pyridazine analogs.