1: Ethyl 6-hydroxybenzothiazole-2-carboxylate With potassium carbonate in N,N-dimethyl-formamide T=20°C; 0.5 h; 2: methyl iodide in N,N-dimethyl-formamide 1 h; Reflux;

ammonium hydroxide in ethanol; water 5 h; Reflux;