Development of an Acyl Sulfonamide Anti-Proliferative Agent, LY573636·Na†

The synthesis of 5-bromo-thiophene-2-sulfonic acid 2,4-dichlorobenzoylamide sodium salt on multikilogram scale is described. The initial clinical supplies were made using carbonyl diimidazole to converge the two fragments. A more efficient acid chloride process has been developed, which also provides better control of impurities and color throughout the synthesis.