2,3-Dichloro-N-(5,6-dichloro-3-methoxy-2-pyrazinyl)-N-{[2-(trimethylsilyl)ethoxy]methyl}benzenesulphonamide (Example 66 part a) (0.20 g), azetidin-3-ol hydrochloride (0.082 g) and triethylamine (0.25 mL) in acetonitrile (3 mL) and water (0.5 mL) was stirred at room temperature. After 2 h, the mixture was evaporated and triturated with diethyl ether. The ethereal solution was evaporated and the residue dissolved in a 1 molar solution of tetrabutylammonium fluoride in THF (6 mL). After 16 h, the reaction mixture was concentrated and chromatography on silica gel eluting with ethyl acetate/isohexane mixtures gave the title compound as a white solid (0.024 g).
