2006

Pyridazine derivativesR 0500 [4 + 2] Cycloaddition of Dimethyl 1,2,4,5-Tetrazine-3,6-dicarboxylate with

EWG-Substituted Primary Ketene N,O-Acetals: Synthesis of Tetrafunctional Pyridazines and Pyrroles. — The [4 + 2] cycloaddition of ketene-O,N-acetals bear-ing an electron-withdrawing substituent with the tetrazine (I) is studied. Reductive treatment of the resulting pyridazines (III) with activated zinc leads to ring contracted pyrroles. A similar sequence involving cyanamide resulting in formation of imidazole (XI). — (MUELLER, J.; TROSCHUETZ*, R.; Synthesis 2006, 9, 1513-1517; Inst. Pharm. Lebensmittelchem., Friedrich-Alexander Univ., D-91052 Erlangen, Germany; Eng.) — Mais

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