Sodium hydride → Tyrima

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Reaction Steps

Solid 3-fluoro-7-hydroxyphenoxathiin 10,10-dioxide (Example 64) (1.092 g, 4.10 mmoles) was added to an ice-bath cooled, stirred mixture of sodium hydride (60% dispersion in mineral oil) (Aldrich) (0.164 g, 4.10 mmole) in N,N-dimethylformamide (20 mL). After 10 minutes, within which effervescence ceased, 2-iodo-1,1,1-trifluoroethaane (4.993 g, 23.78 mmoles) was added and the solution was heated with stirring at 100° C. for 24 hours. The reaction was cooled and added in portions to 100 mL of vigorously stirred ice-water to give a solid, which was collected by suction filtration and washed with water. The solid which was two equal size spots on tlc (silica gel, ethyl acetate-hexanes:1-4) dissolved in dichloromethane (50 mL), absorbed on silica gel 60 and purified by flash column chromatography on silica gel 60. The column was eluted with ethyl acetate-hexanes:1-6 (1 L) and ethyl acetate-hexanes:1-3 (1 L), and the fractions that contained product (the higher Rf spot on tlc) were combined and spin evaporated in vacuo to give 0.731 g (51% yield) of 3-fluoro-7-(2,2,2-trifluoroethoxy)phenoxathiin 10,10-dioxide as a white powder, m.p. 160-161° C.

Provenance & Evidence