Water → HCID 69714493, compound

Participants

Reaction Conditions

Reaction Steps

Ethyl (5-bromo-2-isobutyl-3-oxo-2,3-dihydro-1H-isoindol-1-yl)acetate and ethyl (6-bromo-2-isobutyl-3-oxo-2,3-dihydro-1H-isoindol-1-yl)acetate are prepared as described in Example 2, starting with 5.0 g of 60% sodium hydride in 250 cm3 of 1,2-dimethoxyethane, 24.8 cm3 of triethyl phosphonoacetate and 23.7 g of 5-bromo-3-hydroxy-2-isobutyl-2,3-dihydroisoindol-1-one and 6-bromo-3-hydroxy-2-isobutyl-2,3-dihydroisoindol-1-one. The mixture is refluxed for 4 hours and then cooled to a temperature in the region of 20° C. The reaction mixture is treated with 300 cm3 of water and the mixture is then extracted with 3 times 250 cm3 of diethyl ether. The organic extracts are combined, washed with 300 cm3 of saturated brine, dried over magnesium sulfate, filtered and then concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. The residue is purified by chromatography under argon pressure (80 kPa), on a column of silica gel (particle size 32-63 μm), eluting with successive mixtures of cyclohexane/ethyl acetate (95/5 by volume), cyclohexane/methanol (90/10) and cyclohexane/ethyl acetate (80/20). The fractions comprising the expected product are combined and concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. 3.72 g of ethyl (5-bromo-2-isobutyl-3-oxo-2,3-dihydro-1H-isoindol-1-yl)acetate and ethyl (6-bromo-2-isobutyl-3-oxo-2,3-dihydro-1H-isoindol-1-yl)acetate are thus obtained in the form of a colorless oil. (Rf=0.70, thin layer chromatography on silica gel, eluent: cyclohexane/ethyl acetate (50/50 by volume)).

Provenance & Evidence