1: ethyl 2-hydroxy-5-sulfonicotinoate With thionyl chloride; N,N-dimethyl-formamide in toluene
3 h; Heating / reflux;
2: N-ethyl-piperazine With triethylamine in toluene
T=10 - 20°C; 19.5 h;
3: sodium ethanolate With sodium hydroxide
more than 3 stages;
参考文献
Pfizer Limited; PFIZER INC.
Patent: EP1241170 A2, 2002 ;
Location in patent: Page 70 ;
EP 1241170 A2
