Bicyclo[2.2.1]heptane-1-methanesulfonic acid, 7,7-dimethyl-2-oxo-, (1S)- → HCID 18673945, compound

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Reaction Steps

3.5 g of 3,4-dichloro-N1-{6-(1-oxo-2,3-dihydro-1H-inden-4-yl)oxy]-3-pyridinyl}benzamide obtained in Example 1 was suspended in 140 ml of ethanol. To the suspension, 14 ml of ethyl orthoformate, 820 mg of (±)-10-camphorsulfonic acid and 3.5 g of 4A molecular sieves were added and the mixture was heated at reflux for 30 minutes. After air cooling, the reaction mixture was filtered. To the filtrate, 8.5 ml of an aqueous 1N sodium hydroxide solution was added and the solvent was distilled off under reduced pressure. To the resulting residue, 100 ml of ethyl acetate was added and the solution was washed in turn with water and a saturated sodium hydrogencarbonate solution and then dried over magnesium sulfate. After drying, the solvent was distilled off and the resulting residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate (4:1)) to obtain the titled compound (white powder, 530 mg).

Provenance & Evidence