Hydrochloric Acid → Isopropyl 2-chloro-5-[(6-methyl-2,3-dihydro-1,4-dithiine-5-carbonyl)amino]benzoate

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Reaction Steps

Thionyl chloride (6.5 g, 0.055 mole) was added slowly to a stirred solution of 5,6-dihydro-3-methyl-1,4-dithiin-2-carboxylic acid (3 g, 0.017 mole) in toluene (15 ml) at room temperature. The mixture was heated under reflux for 4 hours. The excess toluene and thionyl chloride were removed in a rotary evaporator, yielding the crude acid chloride. 1-Methylethyl 5-amino-2-chlorobenzoate (3 g, 0.014 mole) in pyridine (20 ml) was added slowly to a stirred solution of the crude acid chloride (3 g) in methylene chloride (20 ml) at 20° C. The mixture was stirred for 24 hours, poured onto ice and concentrated hydrochloric acid, washed twice with water, dried with magnesium sulfate, and the methylene chloride evaporated. Recrystallization from 95% ethanol yielded the title compound, m.p. 122°-124° C. (3 g, 57% yield).

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