Under nitrogen, 0.43 g (1.5 mmol) of 3-isobutylamino-2-methyl-4-(methyl-sulfonyl)benzoic acid, 0.22 g (2.0 mmol) of 1-ethyl-5-hydroxypyrazole and 0.35 g (1.8 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were dissolved in dry acetonitrile. The mixture was stirred at RT for 1 day and allowed to stand for 2 days. 0.42 ml (3.0 mmol) of NEt3, 0.08 ml (0.6 mmol) of Me3SiCN and a spatula tip of KCN were added, and the mixture was stirred at RT for 2 days. The solvent was removed, and the residue was taken up in CH2Cl2 and 10% strength H2SO4. The organic phase was separated off and dried over MgSO4, and the solvent was removed under reduced pressure. The residue was crystallized from acetonitrile. This gave 0.16 g of a red solid of a purity of 96%.
