Methanesulfonic Acid → Methyl 3-(5-amino-1,3,4-thiadiazol-2-yl)propanoate

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Reaction Steps

3-Chlorocarbonyl-propionic acid methyl ester (4.4 g, 21 mmol) is added dropwise to a stirred suspension of thiosemicarbazide (4.0 g, 44 mmol) in THF (25 ml) at 0° C. After stirring at room temperature for 18 h the product which precipitates is removed by filtration and washed with diethyl ether. This product (7.1 g, 34 mmol) is suspended in toluene (30 ml) at 0° C. and methane sulfonic acid (3.37 ml, 52 mmol) is added dropwise to the stirred reaction. The reaction is heated at 70° C. for 3 hours then concentrated at reduced pressure. Methanol (30 ml) is added followed by slow addition of aqueous ammonia, with stirring, until the solution is basic. The titled compound which precipitates is removed by filtration and purified by chromatography on silica, eluting with chloroform-methanol (10:1).

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