Cl[CH2:2][C:3]#[N:4].[K].[C:6]([NH:11][C:12](=[S:16])[O:13][CH2:14][CH3:15])(OCC)=[O:7].C(N(CC)CC)C>CO>[C:3]([C:2]1[S:16][C:12]([O:13][CH2:14][CH3:15])=[N:11][C:6]=1[OH:7])#[N:4]22.8 g of chloroacetonitrile were added dropwise with stirring at room temperature to a suspension of 61.5 g of the potassium salt of ethyl N-carbethoxy-thiocarbamate [described by Guha et al, Indian Chem. Soc., Vol. 6 (1929), p. 570] in one liter of methanol and after stirring the mixture for 2 hours, 30 g of triethylamine were added thereto. The mixture was stirred for another 48 hours and was then refluxed for 2 hours and filtered. The filtrate was concentrated to dryness and the residue was added to sodium hydroxide solution. The resulting solution was washed with ethyl ether, acidified with hydrochloric acid and extracted with ethyl ether. The extracts were dried and evaporated to dryness and the residue was crystallized from petroleum ether to obtain 26.4 g of 5-cyano-4-hydroxy-2-ethoxy-thiazole melting at 132°C.
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