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

In 30.0 ml of tetrahydrofuran (THF), 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 6.97 g of oxalyl chloride at 5° C. to a mixture of 100 ml of THF 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 250 ml of ice water to precipitate crystals. The crystals were collected by filtration and washed with 100 ml of ice water. The resulting crystals were thereafter suspended in water and the suspension was adjusted to pH 4.0 with a 1M aqueous solution of sodium acetate. The resulting solution was extracted with 250 ml of ethyl acetate. The organic layer was dried over magnesium sulfate, followed by filtration. The filtrate was concentrated and, under reduced pressure, was then dried, whereby the title compound was obtained. Yield: 7.5 g (68.7%). Purity: 98.7 %.