2H-thiopyran-2-one → 10-amino-3,4-dihydro-7-fluoro-1H-thiopyrano [4,3-b]quinoline

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Reaction Conditions

Reaction Steps

A mixture of 4-fluoroanthranilonitrile (4.47 g) and freshly fused, pulverized ZnCl2 (6.7 g) in 20 ml of nitrobenzene was heated at 50° C. for 45 minutes. To the resulting suspension was added thiopyran-2-one (5.1 g). This was heated at 130° C. for 3 hours. The resulting precipitate was filtered, rinsed with ether and partioned between 2-butanone and NH4OH solution. The aqueous layer was extracted with 2-butanone and the combined organics were washed with water and dried (MgSO4). This resulted in 4.8 g of a tan solid, m.p. 234°-237° C. d., which was recrystallized from ethyl acetate to give 3.0 g of a white powder, m.p. 235°-237° C. d.

Provenance & Evidence