15-Crown-5 → 2-(2,3,5,6-Tetrafluoro-4-pyridyl)-5-methyl-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide

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Reaction Steps

To a mixture of the sodium salt of 5-methyl-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide (5.2 mmol, prepared by treatment with sodium methoxide) suspended in 30 ml of acetonitrile was added pentafluoropyridine (0.57 ml, 5.2 mmol) and 1.14 g (5.17 mmol) of 15-Crown-5 and DMF (25 ml), and the resulting mixture was refluxed for 20 hours. The mixture was cooled, concentrated in vacuo, and the residue diluted with water, extracted with methylene chloride, and the organic layer was washed with water and brine. The organic layer was concentrated in vacuo and a crude product was purified by flash chromatography to afford 0.39 g (22%) of 2-(2,3,5,6-tetrafluoro-4-pyridyl)-5-methyl-4-propyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide (Formula I: R1 =propyl; R2 =H; R3 =CH3).

Provenance & Evidence