Hexamethylphosphoramide → Ethyl 1-cyclopropyl-7-(2,6-dimethyl-4-pyridinyl)6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate

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Reaction Steps

2,6-Dimethyl-4-(trimethylstannyl)pyridine (part g (10.1 g) and 1.52 g dichlorobis(triphenylphosphine)-palladium was added to a stirred solution of 12.13 g ethyl 7-bromo-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate (part f) and 10 ml hexamethylphosphoramide (HMPA) in 240 ml dioxane under nitrogen. The reaction mixture was heated under reflux for 24 hours, then cooled and partitioned between water and methylene dichloride. The organic extract was washed with sodium chloride solution, dried (magnesium sulfate) and concentrated to give 12.0 g ethyl 1-cyclopropyl-7-(2,6-dimethyl-4-pyridinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate, m.p. 198°-200° C.

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