Cesium carbonate → 4-[5-(2,3-Dichlorobenzenesulphonylamino)-6-methoxy-2-pyrazinyloxy]benzoic acid

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Reaction Steps

4-Hydroxybenzoic acid tert butyl ester (0.13 g), N-(5-bromo-3-methoxy-2-pyrazinyl)-2,3-dichloro-N-[{2-(trimethylsilanyl)ethoxy}methyl]benzenesulphonamide (Example 55 part a) (0.35 g) and caesium carbonate (0.42 g) in acetonitrile (10 mL) was heated at 50° C. After 12 h, the mixture was diluted with ethyl acetate, washed with water, dried (MgSO4) and evaporated. Chromatography on silica gel eluting with ethyl acetate/isohexane mixtures gave the title compound protected with the SEM group and tert butyl group as an oil. The oil was dissolved in trifluoroacetic acid (2.0 mL) and stirred at room temperature for 3 h.

Provenance & Evidence