1H-1,2,4-Triazole → 5-Desfluoro voriconazole, (+/-)-

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Reaction Steps

Methanesulphonyl chloride (1.15 g) was added to a stirred solution of the product of part (iv) (2.35 g) and diisopropylethylamine (2.38 g) in dry tetrahydrofuran (30 ml) at -10° to -20° under an atmosphere of dry nitrogen. The solution was stirred at the same temperature for 1 hour and then anhydrous potassium carbonate (7.0 g) and dry N,N-dimethylformamide (25 ml) were added. The mixture was stirred at room temperature for 1.5 hours and then partitioned between water and ether. The organic layer was separated, washed with water and dried (Na2SO4). Evaporation of the solvent gave an oil which was immediately dissolved in methanol (50 ml). 1H-1,2,4-Triazole (6.0 g) and anhydrous potassium carbonate (6.0 g) were added and the mixture was heated at 60° with stirring for 40 hours, then evaporated. The residue was partitioned between ethyl acetate/ether (1:1) and water, the organic layer was separated and washed with water, then dried (Na2SO4). The solvent was evaporated and the residue was chromatographed on silica gel. Initial elution with ethyl acetate gave impurity-containing fractions, and subsequent further elution with ethyl acetate/methanol (20:1) gave, after combination and evaporation of appropriate fractions, the title compound, (0.87 g), m.p. 55°-58°, [α]D25 -65.1° (0.55% in methanol).

Provenance & Evidence