Hydrochloric Acid → 4-Chloro-2-(2-fluoroethyl)-5-methoxyindan-1-one

Participants

Reaction Steps

To a solution of ethyl 4-chloro-2-(2-fluoroethyl)-5-methoxy-1-oxoindane-2-carboxylate (56.4 g of crude product from the previous reaction) in THF (330 mL) was added methanol (50 mL) followed by a solution of methanol (116 mL)/water (166 mL). To the resulting clear red-orange solution was added SN aqueous NaOH (55.7 mL, 279 mmol) gradually during 9 minutes giving a black solution. After 3.5 hours, the reaction was quenched by addition of 12N aqueous HCl (30 mL, 360 mmol) and most of the THF and methanol were removed by rotary evaporation at reduced pressure. The residue was partitioned between EtOAc and water and the organic phase was washed with saturated aqueous NaHCO3 and brine and dried over MgSO4. Filtration and removal of the solvent under reduced pressure gave crude product. Purification by flash chromatography on silica gel (elution with CH2Cl2) gave the product. Re-purification of mixed fractions gave additional product. The combined yield esd 4-chloro-2-(2-fluoroethyl)-5-methoxyindan-1-one which by NMR contained approximately 4% of the undesired 6-chloro-2-(2-fluoroethyl)-5-methoxyindan-1-one regioisomer.

Provenance & Evidence