A solution of cyclopropanecarboxylic acid (6-hydroxybenzothiazol-2-yl)amide (intermediate 6) (60 mg, 0.256 mmol), pyridine (80 μl, 0.991 mmol), 4-dimethylaminopyridine (3 mg, 0.025 mmol) and 5-(2-pyridyl)thiophene-2-sulfonyl chloride (99 mg, 0.384 mmol) in 2 ml of acetone is stirred for 24 hours at 40° C. The reaction medium is concentrated to dryness, taken up in 2 ml of DMSO and purified 4 times by preparative LC/MS (method B) to give 10 mg of 5-pyridin-2-ylthiophene-2-sulfonic acid 2-(cyclopropanecarbonyl-amino)benzothiazol-6-yl ester.
