3,4,5,6-Tetrahydrophthalic anhydride → 2-(2-Fluoro-4-hydroxyphenyl)-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H)-dione

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Reaction Steps

The filtrate from Step A was mixed with 9.74 g (0.0640 mole) of 3,4,5,6-tetrahydrophthalic anhydride, and the mixture was heated at reflux for approximately 64 hours. At the end of this period, the dark brown solution was poured over ice and extracted in succession with ethyl acetate and diethyl ether. The extracts were combined, washed with water, dried over anhydrous magnesium sulfate, and filtered. The solvents were evaporated under reduced pressure from the filtrate, leaving a dark brown oil as residue. This was placed on a silica gel column and eluted with methylene chloride/-ethyl acetate (95/5). After the product-containing fractions were combined and the solvents evaporated under reduced pressure, 14.71 g of N-(2-fluoro-4-hydroxyphenyl)-3,4,5,6-tetrahydrophthalimide was recovered as an orange solid, m.p. 132°-136° C. The NMR spectrum was consistent with the proposed structure.

Provenance & Evidence