Citric Acid → HCID 22281907, compound

Participants

Reaction Steps

To a solution of 2-{[5-amino-4-(1,3-benzodioxol-5-yl)-1-methyl-1H-pyrazol-3-yl]oxy}ethyl acetate (Preparation 33) (500 mg) in anhydrous pyridine (5 ml) at room temperature and under an atmosphere of nitrogen was added 4-dimethylaminopyridine (191 mg) and 5-isopropyl-2-pyridinesulfonyl chloride (1.72 g). After being left to reflux overnight, the reaction mixture was poured onto saturated citric acid solution (50 ml) and extracted with ethyl acetate (2×50 ml). The organic fractions were washed with brine (50 ml), followed by drying over magnesium sulfate, filtering and concentration under reduced pressure. To a solution of the residue in ethanol (50 ml) was added sodium hydroxide solution (5 ml of 2M). The mixture was stirred overnight before being concentrated to approximately 5 ml under reduced pressure and partitioned between ethyl acetate (2×100 ml) and saturated citric acid solution (100 ml). Washing of the organic fractions with brine (100 ml), drying over magnesium sulfate, filtering and concentration under reduced pressure afforded a brown residue. Purification by column chromatography on silica gel (5 g), eluting in an isocratic fashion with ethyl acetate:hexane (2:1) afforded the title compound as a gum (18 mg).

Provenance & Evidence