Phosphorus oxychloride → 4,6-Dichloro-3-nitroquinoline

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Reaction Steps

11 g (48.97 mmol) 6-chloro-3-nitro-quinolin-4-ol (Example 23b) in 80 ml POCl3 are heated and kept under reflux for 5 h (tlc-control). The cool reaction mixture is poured slowly into 1.5 l ice-water. The title compound separates as a solid. The mixture is stirred for 15 min. the temperature not exceeding 0-5° C. The solid is filtered off, washed with water and dissolved in 200 ml ethylacetate. The organic phase is washed with a mixture of 200 ml water and 38 ml 2N sodium hydroxide solution and again water. After drying over MgSO4, the solvent is evaporated almost to dryness; to the residue hexane is added and the product is isolated by filtration as a dark-grey powder. This material is used in the next step without further purification. mp: 118-120° C.; NMR (DMSO-d6): 9.43/s (1H); 8.43/d (1H), 8.25/d (1H), 8.10/d×d (1H); HPLC: tret=12.84 min (Grad 1).

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