3-Chloro-1,2-propanediol → 1-Fluoro-4-hydroxy-9H-thioxanthen-9-one

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Reaction Steps

The reactant 1-fluoro-4-hydroxy-thioxanthen-9-one was prepared as described above in Example 1a. To a suspension of 1-fluoro-4-hydroxy-9H-thioxanthen-9-on (92%) (306 g, 1.14 mol) in acetonitrile (3500 mL), potassium carbonate (464 g, 3.36 mol) was added while stirring vigorously. 3-Chloro-1,2-propanediol (371 g, 3.36 mol) was added drop wise over 30 minutes. The reaction mixture was heated to reflux and allowed to stir for 24 hours. The mixture was filtered and the residue was washed with warm acetonitrile (500 mL) (70° C.). The filtrate was evaporated under reduced pressure. The residual solid was treated with a mixture of methyl-tert-butylether (400 mL) and acetone (40 ml) and stirred for about an hour. The crude 4-(2,3-dihydroxy-propoxy)-1-fluoro-thioxanthen-9-one was isolated by filtration and dried. The crude 4-(2,3-dihydroxy-propoxy)-1-fluoro-thioxanthen-9-one was treated twice with 1000 mL water at 60° C., isolated by filtration and dried.

Provenance & Evidence