2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 2-Chloro-6-nitroquinoline

Participants

Reaction Conditions

Reaction Steps

6-Nitro-3,4-dihydro-1H-quinolin-2-one (12.56 g, 65.4 mmol) was suspended in toluene (200 mL), to which DDQ (15.06 g, 66.3 mmol) was added. Phosphoryl trichloride (30.5 mL, 327 mmol) was then added dropwise and the reaction mixture was then heated at 90° C. for 3 hours. It was then observed that the deep red semi-solution had become an orange free flowing suspension, which LC-MS confirmed contained desired product. The reaction mixture was then poured slowly into ice water (1 L), keeping temperature below 10° C. This solution was then neutralized to pH 7 via slow addition of 2.5M aq. sodium hydroxide, keeping temperature below 10° C. This brown suspension was then extracted with ethyl acetate. The aqueous layer was back extracted further with ethyl acetate, and the combined organic layers were washed with brine. The resulting orange/brown solution was dried over MgSO4, filtered and concentrated to afford a brown/orange solid, which was dried under high vacuum overnight. The mass of dry material (2-chloro-6-nitro-quinoline) was 7.2 g (50% yield).

Provenance & Evidence