Ethyl 7-bromo-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate → 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 (2.6 g) in dioxane (6 ml) is slowly dropped into a stirred mixture of ethyl 7-bromo-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate (3.1 g), dioxane (55 ml) and hexamethylenphosphoramide (2.6 ml) kept under argon. To the stirred mixture, dichlorobis (triphenylphosphine) palladium (0.4 g) is added. The reaction mixture is heated under reflux for 24 hours. After cooling it is poured in water (200 ml) and repeatedly extracted with dichloromethane. The organic extracts are dried and evaporated to dryness. The residue, after trituration with ethyl ether, gives ethyl 1-cyclopropyl-7-(2,6-dimethyl-4-pyridinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate (2.4 g) m.p. 196°-199° C.

Provenance & Evidence