Sulfur → 2H-1,4-Thiazin-3(4H)-one, 5-methyl-6-(4-pyridinyl)-

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Reaction Conditions

Reaction Steps

The mixture of 5-methyl-6-[1-(2,2,2-trichloroethoxycarbonyl)-1,4-dihydro-4-pyridinyl]-2H-1,4-thiazin-3(4H)-one (2.14 g) and sulfur (10.7 g) was stirred at 140° C. for 1.5 hours and then cooled to room temperature. The obtained solid was extracted with methanol by using Soxhlet extractor. Methanol was evapolated to dryness, and the residue was dissolved in 50 ml of 2N hydrochloric acid. The insoluble solid was removed by filtration and the filtrate was adjusted to pH 7.2 by addition of 2N sodium hydroxide aqueous solution. The precipitates were collected by filtration and the filtrate was extracted with chloroform (20 ml×5 times) and was evaporated to dryness. The combined precipitates and the residue were recrystallized from isopropanol to give 5-methyl-6-(4-pyridinyl)-2H-1,4-thiazin-3(4H)-one (0.88 g, yield 76.5%) as pale yellow plates.

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