Dimethylformamide → (2Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetyl chloride

In 50.0 ml of 1,2-dimethoxyethane (DME), 10.0 g of 2- (5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-methoxyiminoacetic acid were stirred at -20° C., followed by the dropwise addition of a chlorinating reagent, which had been prepared beforehand by gradually adding 8.4 g of phosphorus oxychloride at 5° C. to a mixture of 20 ml of DME and 4.0 g of N,N-dimethylformamide (DMF) and then reacting them for 30 minutes. After they were reacted for 5 minutes, the reaction mixture was poured into 160 ml of ice water to precipitate crystals. The resulting crystals were collected by filtration, washed with 200 ml of ice water and then stirred for 30 minutes in 120 ml of n-hexane. After filtration, the resulting crystals were dried under reduced pressure, whereby the title compound was obtained. Yield: 8.43 g (76.6%). Purity: 97.2%.