6??(substituted phenyl)??5??methyl??4, 5??dihydro??pyridazin??3 (2H)??ones of medicinal interest. The synthesis of SK&F 94836 and SK&F 95654

…, J Mistry, MB Mitchell, KD Pancholi…

Index: Burpitt; Crawford; Davies; Mistry; Mitchell; Pancholi; Coates Journal of Heterocyclic Chemistry, 1988 ,  vol. 25,  # 6  p. 1689 - 1695

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Citation Number: 14

Abstract

Abstract Two synthetic routes to the dihydropyridazinone-cyanoguanidine 4 (SK&F 94836) are described, both proceeding via the anilino compound 6. An efficient synthesis of the dihydropyridazinone-pyridone 5 (SK&F 95654) is reported. This synthesis proceeds via the fluoro-keto-acid 24, with subsequent displacement of the fluoro substituent by 4-pyridone. The surprising effectiveness of water as a solvent in this reaction has been highlighted.